Posted by **zeke** on Sunday, January 7, 2007 at 10:14am.

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

__15__
146

To check to make sure you're right, you'd add

**from the bottom to the top** of each column. If you get the same answer, you know it's right.

15

95

__36__
146

That's called

**adding up**.

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.

## Answer this Question

## Related Questions

- Math - 75 + -63 + 7( 115/ -5 + (-8)2 ) -63 is -6 to the third power and (-8)2 is...
- math - how do you add and subtract + and - numbers? Is there a rule? Yes. The ...
- MATH - What are the 3 property names of addition? 1. The Zero Property of ...
- math - Show how to make one addend the next ten number. complete the new ...
- Grade 3 math - Never thought I would have a problem with Gr. 3 math - lol - but ...
- Geometry - Complete Problem #28 in Section 1.5 Exercises (Chapter 1) of ...
- Algebra 2345678!! - Solve the system of equations using the Addition method. 2a...
- MATH - What is commutative property of addition? The commutative property of ...
- math - if we consider multiplication as repeated addition then it is simple to ...
- bartlett hill,math - add the like terms together.a+b+a+2b Okay. Well, the ...