2. Today we will be learning to explain the methods and reasoning used to complete calculations.

3. Mental Activity We are going to practise adding 3 one-digit numbers. Top Tips Look for pairs that add up to 10. Look for doubles and near doubles.

4. 3 + 5 + 78 + 9 + 36 + 7 + 54 + 8 + 69 + 4 + 1

5. 5 + 4 + 82 + 3 + 88 + 8 + 96 + 5 + 37 + 3 + 7

6. 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.

7. 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?

8. Can you explain your method of calculation for each of these? 33 + 27 = 60 52 - 19 = 33 36 x 2 = 72 84  2 = 42 77 98 - 21 =

9. 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.