Investigation · Year 5

Consecutive Numbers

Multiply the smallest and largest of three consecutive numbers, then square the middle one. What do you notice, and why?

  1. First, choose three consecutive numbers – for example:

    9, 10, 11

    Multiply the smallest number by the largest

  2. 9 x 11

    Square the other number (multiply it by itself):

  3. 10 x 10

    What do you notice?

    Try this with another three consecutive numbers.

    What happens? Why?

  4. Try the whole thing again. This time using numbers which increase by 2 instead of by 1 – for example:

  5. 6, 8, 10

    Multiply the smallest number by the largest

  6. 6 x 10

    Square the other number (multiply it by itself):

  7. 8 x 8

    What do you notice?

    Try this with another set of similar numbers.

    What happens when you explore different sequences of numbers?