Every card in Probability, Year 7: more practice
The whole deck, in order — so you can read it through before your child ever sees it.
- What chance word describes rolling a 7 on a normal six-sided dice?
Impossible
HintLook at the numbers on the faces.
WhyThere is no 7, so the probability is 0. The word is impossible, not just unlikely.
- On a fair dice, which is more likely: an even number or a number greater than 4?
An even number
HintCount how many faces give each result.
WhyEven numbers: 2, 4, 6 — three faces. Numbers greater than 4: 5, 6 — two faces. So even is more likely.
- What probability does a certain event have?
1
HintThink about the right-hand end of the probability scale.
WhyEvery probability lies between 0 (impossible) and 1 (certain). A probability can never be more than 1.
- Which has the greater probability, 0.4 or 3/5?
3/5
HintChange both to decimals first.
Why3/5 = 0.6, which is greater than 0.4.
- A fair coin is flipped twice. List every possible outcome.
HH, HT, TH, TT
HintFix the first flip, then list both possibilities for the second.
WhyEach flip has two results. Taking the first flip in order gives HH, HT, then TH, TT, so four outcomes. HT and TH are different outcomes.
- A fair coin is flipped three times. How many different outcomes are there? (number only)
8
HintEach flip doubles the number of outcomes so far.
Why2 × 2 × 2 = 8. List them systematically to check: HHH, HHT, HTH, HTT, THH, THT, TTH, TTT.
- How many two-digit numbers can be made from the digits 1, 2 and 3 if a digit may be used twice? (number only)
9
HintThere are three choices for the tens digit and three for the units digit.
WhyThe tens digit can be 1, 2 or 3, and for each there are three choices for the units: 3 × 3 = 9.
- Which two-digit numbers can be made from the digit cards 4, 7 and 9 if each card is used once? Give them from smallest to largest.
47, 49, 74, 79, 94, 97
HintStart with each tens digit in turn.
WhyStarting with 4: 47, 49. With 7: 74, 79. With 9: 94, 97. Six numbers in all, 3 × 2 = 6.
- A fair spinner has 5 equal sections. What is the probability of landing on any one section?
1/5
HintFair means every section is equally likely.
WhyThe five equal probabilities must add up to 1, so each is 1/5.
- A game: roll a dice. If it is a 6 I win; otherwise you win. Is the game fair?
No — I win with probability 1/6 and you win with 5/6
HintCompare the chance each player has of winning.
WhyA fair game needs both players to have the same chance. Here one player has 5 faces and the other only one.
1★ KS3-MATH-PRB-0035
2★ KS3-MATH-PRB-0036
3★ KS3-MATH-PRB-0037
4★ KS3-MATH-PRB-0038
5★ KS3-MATH-PRB-0039
6★ KS3-MATH-PRB-0040
7★ KS3-MATH-PRB-0041
8★ KS3-MATH-PRB-0042
9★ KS3-MATH-PRB-0043
10★ KS3-MATH-PRB-0044
Keep what you learn
Here, nothing is saved. In your child’s own sky every card is scheduled — it comes back just before they’d forget it — and the professor who wrote it is one tap away.