Arithmetic Grade Four
Lesson Two: Addition Review
Two Column Addition
When adding numbers with two digits, you add the digits in the ones column
together and the digits in the tens column together like this:
It's almost like you are doing two separate additions. For the ones column
you do the problem 4 + 1 = 5 and for the tens column you do the problem 3 +
4 = 7.
Here's another example:
In this case you add 7 and 2 in the ones column to get 9. In the tens column
you add 1 and 3 to get 4. These problems do not have to be arranged as shown
in the examples. We can rearrange them like this and the answers remain the
same:
34 + 21 = 55
17 + 32 = 49
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If you like doing these problems one way better than the other, you can
rewrite them on a piece of scratch paper when they are presented in the way
you don't like doing them. So, if you are presented with:
You can rewrite it like this on a piece of scratch paper.
Either way the answer will still be the same.
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