Grade 3 · Unit 1: Number and place value

Adding 3-digit numbers

Column addition with regrouping.

Counting visitors

On Friday 348 people visited the zoo. On Saturday 476 came. How many altogether? First estimate: 300 + 500 = 800.

Column addition

Ones: 8 + 6 = 14. Write 4, carry 1 ten. Tens: 4 + 7 + 1 = 12. Write 2, carry 1 hundred. Hundreds: 3 + 4 + 1 = 8. Answer: 824.

Check with the estimate

Our estimate was 800. 824 is close, so the answer is sensible. If we got 7114, we would know we made a mistake.

Adding money

A school bag costs ৳275 and a lunchbox ৳158. Add in columns: 275 + 158 = 433. The total is ৳433.

What I learnt

• I can add 3-digit numbers in columns.
• I can regroup ones and tens.
• I can check with an estimate.