AI generatedNumberKS3 / GCSE

Systematic listing without repetition

Systematic listing without repetition.

  • Fix one choice, then list all the possible next choices.
  • Keep a clear order so nothing is missed or counted twice.

Example 1

List all two-digit numbers made from 1, 2, 3. Do not repeat a digit.

Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.
12, 13, 21, 23, 31, 32. There are 6 numbers.

Example 2

List all two-digit numbers made from 1, 2, 4. Do not repeat a digit.

Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.
12, 14, 21, 24, 41, 42. There are 6 numbers.

Your turn

Question 1

List all two-digit numbers made from 1, 2, 5. Do not repeat a digit.

Check answer
Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.
12, 15, 21, 25, 51, 52. There are 6 numbers.
Question 2

List all two-digit numbers made from 1, 2, 6. Do not repeat a digit.

Check answer
Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.
12, 16, 21, 26, 61, 62. There are 6 numbers.
Question 3

List all two-digit numbers made from 1, 2, 7. Do not repeat a digit.

Check answer
Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.
12, 17, 21, 27, 71, 72. There are 6 numbers.
Question 4

List all two-digit numbers made from 1, 2, 8. Do not repeat a digit.

Check answer
Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.
12, 18, 21, 28, 81, 82. There are 6 numbers.
Question 5

List all two-digit numbers made from 1, 2, 9. Do not repeat a digit.

Check answer
Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.Keep the first digit fixed, then list the other choices.
12, 19, 21, 29, 91, 92. There are 6 numbers.
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