Today we will be learning

to explain the methods and reasoning used to complete calculations.

Mental Activity

We are going to practise adding 3one-digit numbers.

Top Tips

Look for pairs that add up to 10.

Look for doubles and near doubles.

3 + 5 + 7

8 + 9 + 3

6 + 7 + 5

4 + 8 + 6

9 + 4 + 1

5 + 4 + 8

2 + 3 + 8

8 + 8 + 9

6 + 5 + 3

7 + 3 + 7

Main Activity

Today we are going to learn to explain methods of calculation.

Here is a calculation to complete.

64 2 = 32

Think about how you worked out the answer before we check to see if you were right.

Try these calculations.

28 x 2 = 56

45 + 46 = 91

36 - 21 = 15

What strategies did you use to help you to work out the answers quickly?

Can you explain your method of calculation for each of these?

33 + 27 = 60

52 - 19 = 33

36 x 2 = 72

84 2 = 42

7798 - 21 =

Group Work

Add 10 then subtract 1 from one-digit and two-digit numbers.

Work out calculations involving three-digit numbers and describe your strategies.

Add 9 and 11 to different numbers. Subtract 7 and 8 from different numbers.