Asked by zeke

how do you check addition problems by adding up?

Let's use this addition problem as an example.

21
35
___

First you add 1 + 5. To check your work, add up, 5 + 1.



If you have a column of numbers and you go down each column to add them together, that's normal, right?

36
95
<u>15</u>
146

To check to make sure you're right, you'd add <b>from the bottom to the top</b> of each column. If you get the same answer, you know it's right.

15
95
<u>36</u>
146

That's called <b>adding up</b>.

When my mother was working for her father in the family business (long before calculators or computers) and had to add long columns of numbers, adding down was the standard; then adding up was the double-check.

=)


thank you.

thank you,that was very helpful.

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