This document provides lesson instructions for teaching students how to subtract numbers using different methods. It discusses counting backwards on a number line, taking counters away, using arrays and ten squares, and finding one less than a given number. Examples are provided such as 20 - 6 = 14 by counting backwards 6 jumps on a number line, and explaining that 1 less than 4 is 3 because 4 - 1 = 3. Students are asked to practice additional subtraction problems by counting backwards on a whiteboard or number line.

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

3. Sunday p.161-162

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