What Strategies Can Use to Show Subtraction?
56 – 27 = ?
Counting up using 10’s then 1’s:
27 + 10 = 37, 37 + 10 = 47, 47 +3 = 50, 50 + 6 = 56
27 + 10 = 37, 37 + 10 = 47, 47 +3 = 50, 50 + 6 = 56
10 + 10 = 20, 3 + 6 = 9; 20 + 9 = 29
Drawing the tens and ones, using taking and breaking as needed:
Using expanded notation (place value):
56 = 50 + 6 and is also 40 + 16
27 = 20 + 7
40 + 16
- 20 + 7
20 + 9 = 29
16 – 7 = 9, 40 – 20 = 20, 20 +9 = 29
Created by Mary Stroot 2013
Using a number line using 10’s then 1’s (note: this can be done counting
back (in 2 different ways), or counting on)
29
36
46
56
The above number line shows starting at 56, and counting back 27 hops,
in which case where you end up provides the answer.
27
30
36
46
56
29
The above number line shows starting at 56, and counting back until you
reach 27, in which case the number of hops made provides the answer.
27
37
47
50
56
29
The above number line shows starting at 27 and counting on until you
reach 56, in which case the number of hops made provides the answer.
There are other ways to show how subtraction works!! See if you can
discover another way!
Created by Mary Stroot 2013