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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.