Split houses and teen numbers
You learn to split a number into two parts.
How to work it out
- The number in the roof is split over the two rooms below.
- Do you know one room? Take it away from the roof to find the other room.
A worked example
Split 13 into two parts.
There are many ways: 10 + 3, or 9 + 4, or 8 + 5, or 7 + 6.
Another example
Solve 9 + 8 by splitting 8.
- Split 8 into 1 and 7, because 9 + 1 = 10.
- Then: 10 + 7 = 17.
Watch out
You add the two numbers together: with roof 8 and room 5 you put 13.
The rooms together make the roof, so a room can never be bigger than the roof. Subtract.
Tips
- Find a split where one part makes 10 with the other number.
Why it works
You split a number to make addition easier. For example, 13 can be 10 + 3, or 12 + 1, or any other pair that adds to 13.