2
Multiples of 2 and 3 on the chart
Discover Mathematics P3: Term 1, Lessons 21–30
GoalFind multiples of 2 and 3 on the 120 chart and see the patterns in them.
New words
multiple · a number you reach by skip counting; 2, 4, 6, 8 are multiples of 2even number · a multiple of 2; it ends in 0, 2, 4, 6 or 8chart · numbers arranged in rows and columns
Explanation
A multiple of a number is what you get when you skip count by that number. 2, 4, 6, 8 and 10 are multiples of 2. On the 120 chart, the multiples of 2 are every second number, and they all end in 0, 2, 4, 6 or 8. Skip counting by 3 gives 3, 6, 9, 12, 15 and 18. Some numbers are multiples of both 2 and 3, such as 6, 12 and 18. Each multiple is also a product: 3 × 4 = 12, so 12 is the fourth multiple of 3.
Worked examples
Here are the multiples of 3 on the 120 chart: 3, 6, 9, 12, 15, 18, 21 and so on. They make a zig-zag pattern, not straight columns. 3 × 7 = 21, so 21 is the seventh multiple of 3.
On this chart up to 60, the multiples of 2 only are one colour, the multiples of 3 only are another colour, and the circled numbers are multiples of both: 6, 12, 18, 24, 30, 36, 42, 48, 54 and 60.
Is 28 a multiple of 3? Skip count by 3: 24, 27, 30. We jump over 28, so it is not. The number line shows ten jumps of 3 from 0 to 30.
Class activity
Clap and stomp. Count aloud from 1 to 40 with your family. Clap on every multiple of 2 and stomp on every multiple of 3. On which numbers do you clap and stomp at the same time?
Practice
1
Write the first six multiples of 2.
2, 4, 6, 8, 10, 12.
2
Write the first six multiples of 3.
3, 6, 9, 12, 15, 18.
3
Is 34 a multiple of 2? Is it a multiple of 3?
Yes for 2, because it ends in 4. No for 3: the multiples of 3 near it are 33 and 36.
4
The coloured numbers are the multiples of 3 up to 30. Which of them are also multiples of 2?
6, 12, 18, 24 and 30.
5
Rahma counted by 3s: 3, 6, 9, 13. Where did she go wrong?
After 9 comes 9 + 3 = 12, not 13. 13 is not a multiple of 3.