Expected outcomes

The Maths Habit

Both spinners are spun lots of times. Which one lands on red more often?

RRSpinner A
RSpinner B

Spinner A. Half of it is red.

The spinner is red 1 time in every 4. How many reds would you expect?

RR2 redsRRR3 redsRRRRR5 reds

Work out

12 ÷ 2620 ÷ 4530 ÷ 1033 × 515

Probability
How likely something is to happen. It is a number from 0 to 1.
01impossiblecertain
Trial
One go: one spin, one flip or one roll.
R
Expect
How many times you think it will happen. The real number can be a bit more or less.
RR
Fair
Each side or section has the same chance.

Out of
Expect
bottom
top
×trials ÷ bottom
trials
?
  1. 1Fill in the fraction.The bottom goes under Out of. The top goes under Expect.
  2. 2Divide by the bottom.Trials ÷ bottom. Write it by both arrows.
  3. 3Multiply by the top.Top × that number. This is how many you expect.

P(red) = 14. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
1
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
5

P(blue) = 12. How many blues would you expect in 14 spins?

Out of
Expect
1Fill in the fraction.
2
1
2Divide by the bottom.
×7
×7
3Multiply by the top.
14
7

P(red) = 14. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
1
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
5
1Fill in the fraction.2Divide by the bottom.3Multiply by the top.

P(win) = 110. How many wins would you expect in 30 games?

Out of
Expect
1Fill in the fraction.
10
1
2Divide by the bottom.
×3
×3
3Multiply by the top.
30
3

P(red) = 14. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
1
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
5
1Fill in the fraction.2Divide by the bottom.3Multiply by the top.

P(green) = 14. How many greens would you expect in 24 spins?

Out of
Expect
1Fill in the fraction.
4
1
2Divide by the bottom.
×6
×6
3Multiply by the top.
24
6

P(red) = 14. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
1
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
5
1Fill in the fraction.2Divide by the bottom.3Multiply by the top.

P(red) = 12. How many reds would you expect in 18 spins?

Out of
Expect
1Fill in the fraction.
2
1
2Divide by the bottom.
×9
×9
3Multiply by the top.
18
9

1Fill in the fraction.2Divide by the bottom.3Multiply by the top.

1P(red) = 110. How many reds would you expect in 40 spins?

Out of
Expect
1
10
1
2
×4
×4
3
40
4

2P(head) = 12. How many heads would you expect in 10 flips?

Out of
Expect
1
2
1
2
×5
×5
3
10
5

3P(win) = 14. How many wins would you expect in 28 games?

Out of
Expect
1
4
1
2
×7
×7
3
28
7

P(red) = 34. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
3
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
15

P(win) = 310. How many wins would you expect in 20 games?

Out of
Expect
1Fill in the fraction.
10
3
2Divide by the bottom.
×2
×2
3Multiply by the top.
20
6

P(red) = 34. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
3
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
15
1Fill in the fraction.2Divide by the bottom.3Multiply by the top.

P(green) = 710. How many greens would you expect in 30 spins?

Out of
Expect
1Fill in the fraction.
10
7
2Divide by the bottom.
×3
×3
3Multiply by the top.
30
21

P(red) = 34. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
3
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
15
1Fill in the fraction.2Divide by the bottom.3Multiply by the top.

P(blue) = 34. How many blues would you expect in 12 spins?

Out of
Expect
1Fill in the fraction.
4
3
2Divide by the bottom.
×3
×3
3Multiply by the top.
12
9

P(red) = 34. How many reds would you expect in 20 spins?

Out of
Expect
1Fill in the fraction.
4
3
2Divide by the bottom.
×5
×5
3Multiply by the top.
20
15
1Fill in the fraction.2Divide by the bottom.3Multiply by the top.

Sam plants 50 seeds. P(a seed grows) = 910. How many would you expect to grow?

Out of
Expect
1Fill in the fraction.
10
9
2Divide by the bottom.
×5
×5
3Multiply by the top.
50
45

Expected outcomes worksheet, page 1

Expected outcomes worksheet, page 2

Answer sheet

Is it right?
Thumbs up: right. Thumbs down: wrong.

  1. P(red) = 14. 20 spins. Expect 5 reds.

    Right

  2. P(red) = 12. 10 spins. Expect 2 reds.

    Wrong: 10 ÷ 2 = 5

  3. P(win) = 34. 8 games. Expect 2 wins.

    Wrong: 2 × 3 = 6

  4. P(head) = 12. 16 flips. Expect 8 heads.

    Right

  5. P(red) = 110. 50 spins. Expect 10 reds.

    Wrong: 50 ÷ 10 = 5

  1. P(red) = 0.3. How many reds would you expect in 200 spins?

    60

  2. Roll a fair dice 60 times. Will you get exactly 10 sixes?

    Not always

  3. A pin lands point up 3 times in 10 throws. How many point up would you expect in 100 throws?

    30

  1. P(red) = 14. How many reds would you expect in 32 spins?

    8
    Out ofExpect××41321Fill in the fraction.2Divide by the bottom.3Multiply by the top.

  2. P(win) = 310. How many wins would you expect in 40 games?

    12
    Out ofExpect××401Fill in the fraction.2Divide by the bottom.3Multiply by the top.

  3. A coin is flipped 18 times. P(head) = 12. How many heads?

    9
Exit tickets to print