1. © Hamilton Trust Keeping Up Term 1 Week 3 Day 3 Objectives: Subtract two-digit numbers from two-digit numbers and from numbers between 100 and 200 by counting back or by counting up; Choose when to use each strategy.

2. © Hamilton Trust Keeping Up Term 1 Week 3 Day 3 When is it easier to subtract by counting back? 84 – 20 76 – 31 125 – 43 76 - 30 is 46, then -1 = 45 84 - 20 = 64 125 - 40 is 85, then -3 = 82

3. © Hamilton Trust Keeping Up Term 1 Week 3 Day 3 Have you got it? Use ‘counting back’ to solve these subtractions. Remember that -29 is the same as -30, then +1 … 75 – 41 75 – 29 94 – 41 94 – 29 116 – 41 116 – 29 127 – 41 127 - 29

4. © Hamilton Trust Keeping Up Term 1 Week 3 Day 3 So, would you use counting up or counting back to solve these subtractions…? 58 – 27 58 – 22 95 – 39 138 – 75 143 – 22 110 – 19 count up count back count back a multiple of 10 then add one back on count back a multiple of 10 then add one back on

5. © Hamilton Trust Keeping Up Term 1 Week 3 Day 3 The white cell shows the difference between the blue and red numbers. Copy and complete one of the grids, choosing to use counting up or counting back for each subtraction.