Write the numbers in columns so ones are under ones and tens are under tens. Add the ones first. If a column makes 10 or more, write the ones digit in that column and carry the ten to the next column, where it is added with the other digits. Work left, one column at a time. With three numbers a column can make 20 or more; then carry 2 tens.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- regroup
- swap ten ones for one ten (or ten tens for one hundred)
- carry
- move the regrouped ten into the next column
- column
- the digits with the same place value, one under another
Worked examples
47 + 38 = ?
- 1.Ones: 7 + 8 = 15. Write 5, carry 1 ten.
- 2.Tens: 4 + 3 + 1 = 8.
= 85
586 + 247 = ?
- 1.Ones: 6 + 7 = 13. Write 3, carry 1.
- 2.Tens: 8 + 4 + 1 = 13. Write 3, carry 1.
- 3.Hundreds: 5 + 2 + 1 = 8.
= 833
358 + 269 + 177 = ?
- 1.Ones: 8 + 9 + 7 = 24. Write 4, carry 2.
- 2.Tens: 5 + 6 + 7 + 2 = 20. Write 0, carry 2.
- 3.Hundreds: 3 + 2 + 1 + 2 = 8.
= 804
For parents
Method: Column addition
What to say: What do the ones make? Is that more than 9? Where does the ten go?
Common mistakes:
- Writes the ones digit of a column total but forgets to add the carried ten into the next column.
- Writes each column's whole total side by side instead of regrouping.
- Writes the tens digit of a column total and carries the ones digit (the reverse of regrouping).
- Lines the numbers up on the left instead of by place value when they have different numbers of digits.
- Always carries 1, even when a column adds up to 20 or more.