Numbers to 20 · Usually met around P1
Splitting and making numbers
Know one part: count on from it to the whole.
How to do it
Method
Know one part: count on from it to the whole
9 = 4 and 5; 14 = 10 and 4 = 9 and 5
Another way
Two rows
●●●● / ●●●●● → 4 + 5 = 9
In full
A number can be split into two smaller numbers, and two numbers make one number: 9 splits into 4 and 5, and 4 and 5 make 9. Know one part and you can find the other: 9 is 4 and □; counting on from 4 to 9 takes 5 steps, so □ is 5. For a number in the teens, take out the 10 first: 14 is 10 and 4, or 9 and 5. Or lay the number out in two rows and count each row.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
5 and 7 make □.
Show the answer and working
Answer: 12
Count on 7 more from 5: you reach 12.
Example 2
9 can be split into 4 and □.
Show the answer and working
Answer: 5
Counting on from 4 to 9 takes 5 steps, so the other part is 5.
Example 3
Which pair does NOT make 12?
- A. 5 and 7
- B. 4 and 9
- C. 7 and 5
- D. 3 and 9
Choose the right answer
Show the answer and working
Answer: B. 4 and 9
Counting on 9 from 4 doesn't reach 12, so 4 and 9 don't make 12.
Practise it in the game →Numbers to 20 · Free to start, unlimited questions, no download