Class 2 addition and subtraction with regrouping
In Class 2, adding and subtracting grow up. Children move from single digits to two- and three-digit numbers, and — for the first time — they meet regrouping: carrying a ten when a column adds up to ten or more, and borrowing a ten when there aren't enough ones to take away.
Regrouping is the moment a lot of children start to feel that maths is "tricky". It isn't hard, but it does have to be understood rather than memorised. Once a child sees that a carried 1 really is one bundle of ten, the whole thing clicks and stays clicked.
What your child needs to know
- Add two- and three-digit numbers with carrying
- Subtract two- and three-digit numbers with borrowing
- Line numbers up by ones, tens and hundreds before working
- Solve one- and two-step word problems
- Check an answer using the opposite operation
Worked examples
47 + 28
Hint — add the ones first, and regroup if you reach ten or more.
Ones: 7 + 8 = 15. That is 1 ten and 5 ones, so write 5 and carry the 1 ten. Tens: 4 + 2 + 1 = 7. The answer is 75. Check by taking 28 away from 75 — you get back to 47.
63 − 27
Hint — there aren't enough ones to take 7 away, so borrow a ten.
We can't do 3 − 7, so we borrow one ten from the 6 tens. Now we have 13 ones and 5 tens. Ones: 13 − 7 = 6. Tens: 5 − 2 = 3. The answer is 36. Check: 27 + 36 = 63.
156 + 27
Hint — work column by column, ones then tens then hundreds.
Ones: 6 + 7 = 13 — write 3, carry 1 ten. Tens: 5 + 2 + 1 = 8. Hundreds: 1. The answer is 183.
Riya has 34 shells. She finds 19 more on the beach. How many now?
Hint — "more" means we add.
34 + 19. Ones: 4 + 9 = 13 — write 3, carry 1. Tens: 3 + 1 + 1 = 5. Riya has 53 shells.
How Olympiads test this
Olympiads such as SOF IMO and CREST CMO at Class 2 often present addition and subtraction as short word problems, or as missing-number questions such as 34 + ___ = 50. They also like "spot the correct sum" items, where a child checks each option. The arithmetic stays within Class 2 limits; the challenge is reading carefully and choosing the right operation. Steady practice with word problems prepares a child well, without promising any particular exam outcome.
Practice questions
Show 5 practice questions and answers
- 25 + 25 — 50
- 58 − 9 — 49
- Fill the gap: 34 + ___ = 50 — 16
- A basket has 46 apples. 18 are sold. How many are left? — 28
- 123 + 45 — 168
Inside Talyzo: World 2, Food
Addition and subtraction is World 2 in the Talyzo course, themed around food — sharing out snacks, counting what's left, filling the basket. Each question gives a hint before the answer and a full explanation after, so a wrong answer becomes a chance to understand regrouping, not a dead end.
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