1. An alternative subtraction algorithm
Trade-First Subtraction
An alternative subtraction algorithm

2. 12
When subtracting using this algorithm, start by going from right to left. 8 12 2
Ask yourself, “Is the top number bigger in the one’s column?” In this problem the 2 on top is smaller than the 6 on bottom. So I need to regroup, by borrowing from the ten’s column. I can only borrow from ONE place to the left. 5 7 6
Move to the tens column. I cannot subtract 5 from 2, so I need to regroup by borrowing from the hundreds column.
In the hundreds column, 8- 3 does not need regrouping.
Now subtract column by column right to left

3. 2 2 7 7 2 5 - 4 9 8 11 Let’s try another one together 15 16 15 1
Ask yourself, “Is the top number bigger in the one’s column?” In this problem the 5 on top is smaller than the 8 on bottom. So I need to regroup, by borrowing from the ten’s column. 2 2 7
Move to the tens column. I cannot subtract 9 from 1, so I need to regroup.
In the hundreds column, 6-4 does not need regrouping.
Now subtract column by column right to left

4. 6 5 5 9 4 2 - 2 8 7 Let's see if you're right. Congratulations! 13 12
Now, do this one on your own. 6 5 5
Let's see if you're right.
Congratulations!

5. Last one! This one is tricky!9
Last one! This one is tricky! 6 13 10 2 3 4
Let's see if you're right.
Congratulations!