Grade 2 · Unit 1: Number and place value

Adding on paper

Line up the tens and ones.

A shopkeeper adds up prices on paper or a calculator.

Shopping totals

A shopkeeper adds prices to find the total. When numbers are bigger, we can add on paper. First estimate: is the answer about 50? 100?

Tens and ones in columns

Write the numbers in columns: tens under tens, ones under ones. This is column addition. Add the ones: 4 + 5 = 9. Add the tens: 3 + 2 = 5. The total is 59.

Regrouping

Add the ones: 7 + 5 = 12. 12 is 1 ten and 2 ones. Write 2 and carry the ten. We regroup. Add the tens: 4 + 2 + 1 = 7. The total is 72.

Check with an estimate

Round each number to the nearest ten and add. 50 + 30 = 80, and our answer 72 is close. If we had got 612, we would know something went wrong!

What I learnt