7.SP.C.5Common CoreMathStatistics and ProbabilityGrade 7
7.SP.C.5: Probability as a Number from 0 to 1
In plain English: 7.SP.C.5 is the Common Core grade 7 math standard that introduces probability as a number from 0 to 1 that tells how likely a chance event is. Larger numbers mean more likely events. Students learn that a probability near 0 means unlikely, around 1/2 means neither likely nor unlikely, and near 1 means likely, in fraction, decimal or percent form.
Understand that the probability of a chance event is a number between 0 and 1 that expresses the likelihood of the event occurring. Larger numbers indicate greater likelihood. A probability near 0 indicates an unlikely event, a probability around 1/2 indicates an event that is neither unlikely nor likely, and a probability near 1 indicates a likely event.
Common Core State Standards for Mathematics · Domain: Statistics and Probability (SP) · Cluster: Investigate chance processes and develop, use, and evaluate probability models. Also written as 7.SP.5 · Official standard
Students learn to describe chance with a number. A chance event is something that may or may not happen, such as rain tomorrow or a coin landing heads. Its probability is a number from 0 to 1 that tells how likely the event is: 0 means the event is impossible, 1 means it is certain, and larger numbers mean the event is more likely. A probability can be written as a fraction (1/4), a decimal (0.25) or a percent (25%), and all three name the same point on a probability line, a number line from 0 to 1.
Students then interpret probabilities in words, as the standard asks. A probability near 0 describes an unlikely event, one around 1/2 describes an event that is neither unlikely nor likely, and one near 1 describes a likely event. The standard gives no exact cutoffs, so this page uses rough guides: up to about 0.2 is near 0, about 0.4 to 0.6 is around 1/2, and about 0.8 or more is near 1. Finding probabilities from experiments and from equally likely outcomes comes next, in 7.SP.C.6 and 7.SP.C.7; here the probabilities are given, or come from simple spinners and number cubes.
Learning Objectives
By the end of this lesson, students will be able to:
Explain why every probability is a number from 0 to 1, and spot numbers that cannot be probabilities
Compare and order probabilities written as fractions, decimals and percents, and say which event is more likely
Describe an event with probability near 0, around 1/2 or near 1 in words: unlikely, neither likely nor unlikely, or likely
Place events on a probability line and explain the difference between unlikely and impossible, and between likely and certain
Prior Knowledge Required
Students should already be comfortable with:
Comparing fractions with different denominators, for example 4/5 and 5/7 4.NF.A.2
Writing a fraction as a decimal by dividing, for example 7/8 = 0.875 7.NS.A.2
Percents as a rate per 100, for example 35% = 35/100 = 0.35 6.RP.A.3
Placing fractions and decimals on a number line 6.NS.C.6
Write four events on the board and ask students to rank them from least likely to most likely, then compare with a partner:
Warm-Up Prompt
"Rank these from least likely to most likely: (a) A flipped coin lands heads. (b) You roll a 9 on a regular number cube. (c) It gets dark tonight. (d) A song picked at random from a playlist of 40 songs is your favorite song." Where would you put each one on a line from 'no chance' to 'sure to happen'?
Most pairs agree on the order b, d, a, c. A number cube is a six-sided cube with the numbers 1 to 6, so a 9 cannot happen, while darkness tonight is sure to happen. Draw a line on the board with "no chance" at the left and "sure to happen" at the right, and tell students that mathematicians label these ends 0 and 1. Every chance event gets a number somewhere between them.
Direct Instruction20 minutes
Draw the probability line (Diagram 1) and label the five key words: impossible (0), unlikely (near 0), neither likely nor unlikely (around 1/2), likely (near 1) and certain (1). Then work through these examples.
Which numbers can be probabilities?
Decide which of these could be the probability of an event: 0.62, 5/4, -0.3, 100%, 0.
Equation: 0.62 is between 0 and 1, so yes. 5/4 = 1.25 is greater than 1, so no: nothing is more likely than certain. -0.3 is less than 0, so no: nothing is less likely than impossible. 100% = 1, so yes: a certain event. 0 is yes: an impossible event.
Larger numbers mean more likely
Three basketball players shoot free throws. The probability that each one makes the next shot: Ari 0.8, Bea 3/4, Cam 78%. Who is most likely to make the next shot?
Equation: Write each as a decimal: Ari 0.8, Bea 3/4 = 0.75, Cam 78% = 0.78. In order: 0.75 < 0.78 < 0.8, so Ari is most likely to make it, then Cam, then Bea. All three are more likely than not to make it, and Ari's 0.8 is near 1: likely.
Near 0, around 1/2 and near 1
A fair number cube (each face 1 to 6 has the same chance) is rolled once. The probabilities are: rolling a 6, 1/6; rolling an even number, 1/2; rolling a number less than 6, 5/6; rolling a 7, 0; rolling a number from 1 to 6, 1.
Equation: 1/6 ≈ 0.17 is near 0: unlikely. 1/2 is neither likely nor unlikely. 5/6 ≈ 0.83 is near 1: likely. 0 is impossible, and 1 is certain. Diagram 1 shows all five on the probability line.
Unlikely is not impossible
A weather app says there is a 10% chance of rain today and a 90% chance of rain tomorrow. Describe each day. Can it rain today?
Equation: 10% = 0.1, near 0: rain today is unlikely, but it is not impossible, because 0.1 is not 0. 90% = 0.9, near 1: rain tomorrow is likely, but not certain, because 0.9 is not 1. Rain is 9 times as likely tomorrow as today.
Diagram 2 shows three spinners, each divided into 8 equal parts. When all parts are the same size, each part is equally likely, so the probability of blue is the number of blue parts out of 8. More blue parts give a larger probability and a more likely event. Ask: "How many parts would be blue if landing on blue were certain? Impossible?" (8 and 0.)
Stress two ideas. First, compare probabilities as numbers, not by their digits: 0.8 is larger than 0.75 even though 75 is larger than 8. Second, the words are about closeness. A probability of 0.04 is unlikely, and 0.96 is likely, but neither is impossible or certain. The rough guides on Diagram 1 help, but a probability such as 0.3 is simply "less likely than not", with no exact word.
Guided Practice15 minutes
Pairs write each probability as a decimal, place it on a probability line drawn on their paper and describe it in words. Then they order all five events from least likely to most likely.
Guided practice events with answers
Event
Decimal
Description
A weather app gives a 90% chance of sunshine tomorrow
0.9
near 1: likely
A fair coin lands heads
1/2 = 0.5
neither likely nor unlikely
A game spinner lands on the jackpot space, probability 1/40
0.025
near 0: unlikely
A strong free-throw shooter makes the next shot, probability 0.85
0.85
near 1: likely
A bag holds only red and blue marbles; you pull out a purple one
0
impossible
Order from least to most likely: the purple marble (0), the jackpot (0.025), heads (0.5), the free throw (0.85), sunshine (0.9). Listen for students who call 1/40 likely because 40 is a large number, and ask them to divide first: 1 ÷ 40 = 0.025. Ask: "Is 0.025 impossible?" (No, just unlikely.)
Independent Practice15 minutes
Students work alone. For each probability, write it as a decimal and as a percent, mark it on a probability line, and choose a word: impossible, unlikely, neither likely nor unlikely, likely or certain. Then write a real event that could have that probability.
Independent practice probabilities with answers
Probability
Decimal and percent
Word
3/4
0.75 = 75%
more likely than not (just below the rough band for near 1; accept likely with a reason)
1/20
0.05 = 5%
unlikely
11/20
0.55 = 55%
neither likely nor unlikely
1
1 = 100%
certain
0.9
0.9 = 90%
likely
Early finishers answer: "Which two of these events are closest in likelihood?" (0.9 and 1, which are 0.1 apart; 0.75 and 0.9 are 0.15 apart.)
Closure5 minutes
Exit ticket: (1) Order from least to most likely: 0.35, 7/10, 5%. (Answer: 5%, 0.35, 7/10.) (2) An event has probability 0.01. Is it impossible? Explain. (Answer: no, it is unlikely; only 0 means impossible.) (3) In one sentence: why can a probability never be 1.5?
Differentiation Strategies
For Struggling Students
Give a printed probability line with tick marks every 0.1 and the five words already written, so students only place the points
Convert every probability to a decimal first, then compare, using a place-value chart for numbers such as 0.8 and 0.75
Use a physical spinner with 8 equal parts and let students color and spin before they work with numbers only
For Advanced Students
Ask students to find a spinner with 8 equal parts whose probability of blue is exactly halfway between 1/8 and 1/2, or to explain why none exists
Have students collect real forecasts (rain chances for a week) and rank the days, then check afterwards which days had rain
Ask students to write two events with the same probability written in two different forms, such as 3/5 and 60%
Assessment Guidance
What to Look For
Check that students keep every probability between 0 and 1 and reject numbers such as 1.2 or -0.1. When they compare, they should rewrite fractions and percents as decimals (or use common denominators) instead of comparing digits. Their words should match the size of the number: unlikely near 0, neither likely nor unlikely around 1/2, likely near 1. Listen for the difference between unlikely and impossible, and between likely and certain.
02
Classroom Activities
3 Activities
1
Human Probability Line
15 minWhole class, then groups of 3
Tape a line about 5 m long on the floor. Mark 0 at one end, 1 at the other, and 0.5 in the middle. Each group gets one or two of the 10 event cards, finds or reads the probability, and stands at that spot on the line holding the card.
Event Cards
E1: A bag holds 10 cubes, all green. You pull out a green cube.
E2: You roll a 0 on a number cube with faces 1 to 6.
E3: A fair coin lands tails.
E4: A weather app gives an 85% chance of rain.
E5: A raffle ticket wins when 1 of 200 tickets is drawn.
E6: A spinner with 8 equal parts, 2 of them red, lands on red.
E7: A good soccer player scores on a penalty kick, probability 0.75.
E8: A spinner with 6 equal parts, 3 of them yellow, lands on yellow.
E9: A school bus arrives on time, probability 96%.
E10: A thrown dart hits the one small bull's-eye, probability 0.04.
Answer Key
E1: 1, certain
E2: 0, impossible
E3: 1/2, neither likely nor unlikely
E4: 0.85, likely
E5: 1/200 = 0.005, unlikely
E6: 2/8 = 0.25, less likely than not
E7: 0.75, more likely than not
E8: 3/6 = 0.5, neither likely nor unlikely
E9: 0.96, likely
E10: 0.04, unlikely
Discussion Questions
E3 and E8 stand at the same spot. Why can two different events have the same probability?
E5 and E10 are both unlikely. Which one is less likely, and how far apart do they stand? (The line is 5 m long, so 0.1 is 50 cm.)
Only E1 stands at 1 and only E2 at 0. Why are the ends of the line so rarely used for real events?
Modification for Distance Learning
Use a shared slide with a long probability line. Students drag labeled sticky notes to the right spot and explain one placement in the chat.
2
Design a Spinner
15 minPairs
Each pair gets three circles divided into 8 equal parts. They color the parts so that landing on red is (a) unlikely, (b) neither likely nor unlikely and (c) likely, write each probability as a fraction and a decimal, and then test one spinner with a paper clip and a pencil.
Procedure
For each circle, decide how many of the 8 parts to color red and write the probability of red, for example 5/8 = 0.625.
Place your three probabilities on a class probability line on the board.
Spin the "likely" spinner 10 times and tally red and not red. Did red come up more often than not?
Answer Key
Unlikely: 1 red part (1/8 = 0.125); 0 parts would make red impossible, not unlikely
Neither likely nor unlikely: 4 red parts (4/8 = 1/2 = 0.5)
Likely: 7 red parts (7/8 = 0.875); 8 parts would make red certain
2 or 6 red parts (0.25 or 0.75) are less clear cases; accept them with a reason
Discussion Questions
Is there a spinner with 8 equal parts that gives a probability of red of exactly 0.6? Explain. (No: the possible values are 0, 0.125, 0.25 and so on, in steps of 0.125.)
Your "likely" spinner may have landed on red fewer times than you expected. Does that mean the probability is wrong?
Challenge Variation
Pairs design a spinner with 8 equal parts in three colors so that red is the most likely color, blue is unlikely, and yellow is neither likely nor unlikely, or explain why this is not possible. (It is not possible: yellow would need about 4 parts and red would need more than yellow, which leaves no parts for blue.)
3
Probability War
15 minPairs
Each pair shuffles a deck of 16 probability cards and deals them face down. Both players turn over a card at the same time; the card showing the more likely event wins both cards. Three cards are not probabilities at all: a player who turns one over must say why, and the other player wins that round.
Write both cards as decimals before deciding. The cards in order from least to most likely: 0, 0.05, 0.125, 0.3 and 3/10 (a tie), 1/3, 7/20, 45%, 0.6, 5/8, 9/10, 92%, 1.
Not probabilities: 1.2 and 130% (greater than 1) and -0.4 (less than 0).
A tie (0.3 against 3/10) means both players turn over another card.
Discussion Questions
Which pair of cards was the hardest to compare? How did you decide?
How many cards show an event that is more likely than not? (Five: 0.6, 5/8, 9/10, 92% and 1.)
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: The Probability Line
Every probability is a number from 0 (impossible) to 1 (certain), and numbers farther right mean more likely events. The shaded bands are rough guides for near 0, around 1/2 and near 1. The dots show the number cube probabilities from Example 3: 0, 1/6, 1/2, 5/6 and 1. Drawn to scale, 56 pixels per 0.1.
Diagram 2: Spinners with 8 Equal Parts
Each spinner has 8 equal parts, so each part is equally likely. With 1, 4 and 7 blue parts, the probability of blue is 1/8 = 0.125 (unlikely), 4/8 = 0.5 (neither likely nor unlikely) and 7/8 = 0.875 (likely). More blue parts give a larger probability and a more likely event.
04
Homework Assignment
~30 min
7.SP.C.5 Homework: Probability from 0 to 1
Directions: Show your work. Write fractions and percents as decimals before you compare them, and explain every answer in a sentence. Use these words where they fit: impossible, unlikely, neither likely nor unlikely, likely, certain.
Part 1: Probabilities as Numbers (Problems 1-3)
Which of these numbers could be probabilities? 0.45, 3/2, 0, -1/4, 81%, 1, 1.05, 2/9. For each number that cannot be a probability, explain why.
Five events have these probabilities: A: 16/25, B: 0.6, C: 57%, D: 0.08, E: 1/3. Write each as a decimal, order the events from least likely to most likely, and name the most likely event.
Write each probability as a decimal and a percent, and describe the event with one of the five words: (a) 3/25 (b) 0.49 (c) 91% (d) 0.
Part 2: Interpreting Probabilities (Problems 4-6)
A mountain town's forecast gives the chance of snow as 9% on Friday, 50% on Saturday and 98% on Sunday. Describe the chance of snow on each day in words. On which day is snow likely, and on which day is it still possible but unlikely?
Find and fix each mistake. (a) Maria says, "The chance of hail is 8%, so it will not hail." (b) Omar says, "The probability that our bus is on time is 0.99, so it is certain to be on time."
A spinner has 10 equal parts. How many parts should you color red so that landing on red is (a) unlikely, (b) neither likely nor unlikely, (c) likely? Give each probability as a fraction and a decimal. Then explain why no coloring gives a probability of red of 11/10.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
No Credit (0 pts)
Range of Probability
Keeps every probability from 0 to 1 and explains why other numbers are not probabilities
Spots the invalid numbers without a reason
Accepts numbers below 0 or above 1
Comparing
Converts to decimals correctly and orders every event
One conversion or ordering error
Compares digits instead of values
Describing Likelihood
Words match the numbers, including unlikely versus impossible and likely versus certain
Words mostly match, one mix-up
Words do not match the numbers
Explaining
Every answer has a clear sentence
Some answers without a sentence
No explanations
05
Quiz: 20 Questions
Interactive, with answers
Instructions
Work through the questions in order. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
Which number could be the probability of an event?
Answer: C
A probability must be from 0 to 1, and 4/9 ≈ 0.44 is. Choice A is greater than 1. Choice B is less than 0. Choice D is 120% = 1.2, which is greater than 1: nothing is more likely than certain.
Question 2 of 20 · Multiple Choice
Which probability describes the most likely event?
Answer: B
As decimals: 0.09, 0.7, 0.4 and 0.61. The largest is 7/10 = 0.7, so it is the most likely. Choice A may look large because 9 is a big digit, but 0.09 is less than 0.1. Choice C is 2/5 = 0.4. Choice D, 0.61, has more digits than 0.7 but is smaller.
Question 3 of 20 · Multiple Choice
The probability that a certain rare plant blooms this week is 0.03. How would you describe this event?
Answer: D
0.03 is near 0, so the event is unlikely, but it is not 0, so it can happen. Choice A would need a probability of exactly 0. Choice B describes probabilities around 1/2. Choice C describes probabilities near 1.
Question 4 of 20 · Multiple Choice
A delivery app says the probability that your order arrives on time is 0.97. How would you describe this event?
Answer: A
0.97 is near 1, so on-time arrival is likely. Choice B would need a probability of exactly 1, and 0.97 leaves a small chance of a late order. Choice C fits a probability around 1/2. Choice D fits a probability near 0.
Question 5 of 20 · Multiple Choice
Which probability describes an event that is neither likely nor unlikely?
Answer: C
0.52 is very close to 1/2 = 0.5, so the event is about as likely to happen as not. Choice A is near 0 (unlikely). Choice B is near 1 (likely). Choice D is certain.
Question 6 of 20 · Multiple Choice
An event has a probability of 0. What does this mean?
Answer: B
A probability of 0 is the left end of the probability line: the event is impossible. Choice A describes a probability of 1. Choice C describes a small probability such as 0.05, which is not 0. Choice D describes a probability around 1/2.
Question 7 of 20 · Multiple Choice
Order these probabilities from least likely to most likely: 33%, 3/8, 0.4.
Answer: C
As decimals: 33% = 0.33, 3/8 = 0.375 and 0.4. So the order is 33%, 3/8, 0.4. Choice A lists them from most to least likely. Choice B puts 3/8 first because its digits are small, without dividing. Choice D puts 3/8 last because its denominator 8 is large.
Question 8 of 20 · Multiple Choice
The chance of rain is 20% on Monday, 1/2 on Tuesday, 3/20 on Wednesday and 0.65 on Thursday. On which day is rain more likely than not?
Answer: D
"More likely than not" means a probability greater than 1/2. Only Thursday's 0.65 is greater than 0.5. Choice A is 0.2 and Choice C is 3/20 = 0.15, both less than 1/2. Choice B is exactly 1/2: rain is as likely as not, not more likely.
Question 9 of 20 · Multiple Choice
A school raffle says the probability of winning the grand prize with one ticket is 0.001. Which statement is true?
Answer: B
0.001 is very close to 0, so winning is unlikely, but it is greater than 0, so a ticket can win. Choice A confuses unlikely with impossible. Choice C treats the probability as a promise about 1,000 tries. Choice D uses the number of tickets instead of the probability.
Question 10 of 20 · Multiple Choice
A spinner has 5 equal parts numbered 1 to 5. Sam says, "The probability of spinning a 3 is 3." What is wrong with his statement?
Answer: A
A probability is a number from 0 to 1, so 3 cannot be one. The 3 is 1 of 5 equally likely parts, so the probability is 1/5. Choice B confuses the number on the part with its probability. Choice C, 3% = 0.03, is too small: 1/5 is 20%. Choice D would mean every spin lands on 3.
Question 11 of 20 · Multiple Choice
A weather app gave a 15% chance of rain, and it rained. Was the app wrong?
Answer: C
A 15% chance (0.15) is near 0, so rain was unlikely, but events with small probabilities still happen sometimes. Choice A treats 15% as 0. Choice B judges the probability by what happened afterward. Choice D reads the percent as a length of time.
Question 12 of 20 · Multiple Choice
A bag holds 19 red cubes and 1 blue cube. The probability of pulling out a red cube without looking is 19/20. How would you describe pulling out a red cube?
Answer: A
19/20 = 0.95 is near 1, so pulling out red is likely. Choice B describes the blue cube, whose probability is 1/20 = 0.05. Choice C fits a probability around 1/2. Choice D would need no red cubes at all.
Question 13 of 20 · Multiple Choice
Event X has probability 5/9 and event Y has probability 0.6. Which is more likely?
Answer: B
5 ÷ 9 ≈ 0.556, which is less than 0.6, so Y is more likely. Choice A compares the digits 9 and 6 instead of the values. Choice C is right that both are around 1/2, but 0.56 and 0.6 are not equal. Choice D is false: write both as decimals to compare.
Question 14 of 20 · Multiple Choice
Event P has probability 4/10 and event Q has probability 0.4. Which is more likely?
Answer: D
4/10 = 0.4, so the two probabilities are the same number and the events are equally likely. Choice A compares the digits instead of the value. Choice B is wrong: 4/10 and 0.4 are equally exact. Choice C is wrong: converting to decimals makes any two probabilities comparable.
Question 15 of 20 · Short Answer
Write each probability as a decimal, order them from least likely to most likely, and describe each one in words: 0.88, 12/25, 2%, 3/50, 1.
Decimals: 0.88, 12/25 = 0.48, 2% = 0.02, 3/50 = 0.06, 1. Order: 2%, 3/50, 12/25, 0.88, 1. Words: 2% and 3/50 are unlikely (near 0), 12/25 is neither likely nor unlikely (around 1/2), 0.88 is likely (near 1), and 1 is certain.
Question 16 of 20 · Short Answer
Explain why 1.75 and -0.6 cannot be probabilities. What do the probabilities 0 and 1 mean?
A probability measures likelihood on a scale from 0 to 1. 0 means impossible and 1 means certain. Nothing can be less likely than impossible, so -0.6 is not a probability, and nothing can be more likely than certain, so 1.75 is not a probability.
Question 17 of 20 · Short Answer
Lena says, "A probability of 0.25 is greater than a probability of 1/3, because 25 is greater than 3." Is she right? Explain.
No. 1/3 ≈ 0.333, and 0.25 < 0.333, so an event with probability 1/3 is more likely. Lena compared the digits 25 and 3 instead of the values. Writing both as decimals (or as fractions, 1/4 and 1/3) shows that 1/3 is larger.
Question 18 of 20 · Short Answer
Give one real event for each description, with a probability for it: (a) near 0, (b) around 1/2, (c) near 1.
Sample answers: (a) a raffle ticket winning when 1 of 500 tickets is drawn, probability 1/500 = 0.002; (b) a fair coin landing tails, 1/2; (c) a phone app saying there is a 95% chance of sunshine on a summer day in a dry climate. Any events work if the numbers fit the words: close to 0, close to 1/2, close to 1.
Question 19 of 20 · Short Answer
At a fair, Spinner A gives a win with probability 7/25, and Spinner B gives a win with probability 0.32. Which spinner should you choose? Is winning likely with either spinner?
7/25 = 0.28 and 0.32 > 0.28, so Spinner B gives the better chance. But both probabilities are less than 1/2, so with either spinner winning is less likely than losing. Neither probability is tiny, so a win is not rare either.
Question 20 of 20 · Short Answer
A forecaster says the probability of a thunderstorm is 0.82 on Saturday and 0.38 on Sunday. Describe each day, say which day is more likely to have a storm, and explain why a storm on Sunday is still possible.
Saturday's 0.82 is near 1, so a storm is likely. Sunday's 0.38 is less than 1/2, so a storm is less likely than not. Since 0.82 > 0.38, Saturday is more likely to have a storm. A storm on Sunday is still possible because 0.38 is greater than 0; only a probability of 0 would rule it out.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does 7.SP.C.5 mean?
7.SP.C.5 means students understand probability as a number from 0 to 1 that tells how likely an event is. Larger numbers mean more likely events. A probability near 0 means unlikely, around 1/2 means neither likely nor unlikely, and near 1 means likely.
What grade is 7.SP.C.5, and what comes after it?
It is a grade 7 standard in the Statistics and Probability domain, and it is usually the first probability standard students meet. Right after it, students estimate probabilities from repeated trials (7.SP.C.6), build probability models (7.SP.C.7) and find probabilities of compound events such as two coin flips (7.SP.C.8). In high school, students describe events with unions, intersections and complements (HSS.CP.A.1).
Why can't a probability be greater than 1 or less than 0?
Because 0 stands for impossible and 1 stands for certain. No event can be less likely than impossible or more likely than certain, so every probability falls between them. A number such as 1.3 or -0.2 on a worksheet is always a mistake.
What does a probability of 1/2 mean?
A probability of 1/2 means the event is as likely to happen as not to happen. The standard describes it as neither unlikely nor likely. A fair coin landing heads is the usual example.
Is an unlikely event the same as an impossible event?
No. An impossible event has a probability of exactly 0 and can never happen, while an unlikely event has a small probability, such as 0.1, and can still happen. In the same way, a likely event (0.9) is not certain (1).
Where does "near 0" end and "around 1/2" begin?
The standard does not give exact cutoffs, so there is no official line. Many teachers use rough guides, such as up to about 0.2 for near 0 and about 0.4 to 0.6 for around 1/2. Numbers in between, such as 0.3, are best described as "less likely than not."
How do percents and fractions fit into 7.SP.C.5?
They are other ways to write the same probability. A 25% chance, 1/4 and 0.25 all name the same point on the probability line. To compare probabilities in different forms, students write them all as decimals first (7.NS.A.2).
How is 7.SP.C.5 tested?
Test items usually ask students to pick a word for a given probability, to order events by likelihood, or to spot a number that cannot be a probability. Some items give a situation, such as a weather forecast, and ask which day an event is most likely.
How can parents help with 7.SP.C.5 at home?
Talk about chance in everyday life. Look at the rain chance in a weather app together and ask: "Is that likely or unlikely? Could it still rain at 20%?" You can also ask your child to place events, such as a school snow day or a sports team winning, on a line from 0 to 1.
What mistakes should teachers watch for?
A common mistake is comparing the digits instead of the values, for example thinking 0.3 is more than 2/5 or that 1/8 is more likely than 1/5. Students also treat unlikely as impossible, read a percent chance as a promise, or accept a probability greater than 1.
07
Related Standards
6 standards
These standards connect to 7.SP.C.5: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
4.NF.A.2Prerequisite
Compare two fractions with different numerators and denominators
Lesson coming soon
7.NS.A.2Prerequisite
Multiply and divide rational numbers, including writing fractions as decimals
