1. Activity 1: 5 columns
Write the multiples of 9 into the table below. What patterns do you notice? Colour the odd numbers yellow and the even numbers blue. What patterns do you notice now?
Write about what you notice: 9 18 27

2. Multiple of 9 Digital Sum 9 18 27 36 45 54 63 72 81 90 99
Activity 2: Digital Sums
Calculate the digital sums of the multiples of nine by adding the digits in each number, e.g. 18 -> = 9
Is there a pattern in the digital sums?
Plot the series on the circle below. What do you notice?
Multiple of 9
Digital Sum 9 18 27 36 45 54 63 72 81 90 99 1 2 3 4 5 6 7 8 9

3. Activity 3: Ones place
What number is in the ones place in the multiples of 9? Is there a pattern in the ones place? Will it repeat?
Plot the series on the circle below. What do you notice?
Multiple of 9
Ones digit 9 18 27 36 45 54 4 63 72 81 90 99 9 1 8 2 7 3 6 4 5