Mental Math-Addition and Subtraction

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Mental math refers to performing calculations in your head without the use of calculators or paper.

The commutative property of addition states that changing the order of the addends does not change the sum (e.g., a + b = b + a).

The associative property of addition states that the way in which numbers are grouped does not change their sum (e.g., (a + b) + c = a + (b + c)).

Addition is the process of finding the total or sum by combining numbers, while subtraction is the process of finding the difference by taking one number away from another.

You can check your addition by using the inverse operation of subtraction to see if the sum matches the original numbers.