To add 34 + 25, split each number into tens and ones. Add the tens: 30 + 20 = 50. Add the ones: 4 + 5 = 9. Then put them together: 59.
Sometimes the ones make more than ten. For 47 + 36, the tens make 70 and the ones make 13. 13 is one ten and 3 ones, so the total is 70 + 13 = 83. This is called regrouping.
Worked example
58 + 27 =
- Tens: 50 + 20 = 70. Ones: 8 + 7 = 15.
- 15 is 1 ten and 5 ones, so 70 + 15 = 85.
Answer:85
Key words
- regroup
- swap ten ones for one ten
- sum
- the answer to an addition
- split
- break a number into tens and ones
Practise this
New questions every time.
Common Core-referenced: 2.NBT.B.5