| Here's another one:
Stack the numbers and line things up in stripes:
Subtract down the stripes...
First, subtract
the ones:
|
Then, subtract the tens:
|
|
That's really
|
|
Here are some problems to practice. Be sure to get really good at these before going to the next lesson. You don't have to do ALL of them... Just do as many as you need to until they feel easy.
| 1) 38-17 |
9) 39-27 |
| 2) 56-21 |
10) 52-31 |
| 3) 88-42 |
11) 73-52 |
| 4) 81-50 |
12) 97-64 |
| 5) 45-32 |
13) 89-69 |
| 6) 95-72 |
14) 83-41 |
| 7) 59-37 |
15) 43-22 |
| 8) 63-12 |
16) 66-13 |
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