Math: count to subtract sunday - Monday week 1
- 1. Lesson: Count to Subtract p.161-164
- 2. Objective: students count back the number they subtract or count on the distance between two numbers
- 4. How many different ways can we subtract numbers?
- 5. We can… Use our fingers to subtract numbers. 10 - 3 = 7
- 6. We can… Use counters and take them away. 16 - 7 = 9
- 7. We can… Use arrays and ten squares to help us. 18 - 5 = 13
- 8. Another way to subtract numbers is to count backwards. We can do this using a number line. 20 - 6 = 14
- 9. Remember, don’t count the number you start on, count the jumps! 19 - 8 = 11 Try one on your number line or whiteboard. Start on 19 and make 8 jumps backwards to get the answer.
- 10. Now let’s try subtraction from 30. 30 - 6 = 24
- 11. p.161
- 12. p.162
- 13. p.162
- 14. Monday p.163-164
- 15. When we find 1 less than a given number, we take away 1 from it. Look at this number line. If we want to find 1 less than a number, all we need to do is look at the number and jump back 1 space on the number line. For example, if we want to find 1 less than 4 we can put our finger on 4 and jump backwards 1 space to 3! 1 less than 4 is 3, because 4 – 1 = 3
- 16. What is 1 less than 7? 7 – 1 = 6
- 17. 10-5= ? Can you show me how to do it on the number line ?
- 18. 17 - 8 = 9 23 - 7 = 16 On your whiteboards or number lines, work out these subtraction calculations by counting backwards: 15 - 7 = 8 27 - 9 = 18 19 - 14 = 5 20 - 8 = 12 20 - 9 = 11 30 - 6 = 24