Mental math
is doing math in your head. You can group addends to help you
find the sum.
Parentheses
may be used without changing the sum.
(5 + 3) + 6 = 14 and 5 + (3 + 6) = 14
The order of the addends doesn't change the sum.
3 + 4 = 7 and 4 + 3 = 7
When you add many numbers together, use one of these ways to help you.
To find the sum of 6 + 4 + 3 + 7 + 2 group them in the easiest way.
6 + 4 = 10 and 3 + 7 = 10, so 10 + 10 + 2 = 22
Practice mental math methods. Fill in the sums.
3 + 7 + 5 + 6 + 9 =
9 + 5 + 1 + 1 + 9 =
13 + 1 + 7 + 2 =
21 + 4 + 10 + 10 =
19 + 5 + 1 + 5 =
8 + 1 + 10 + 9 =
7 + 5 + 4 + 4 =
6 + 6 + 6 + 2 =
11 + 4 + 4 + 2 =
12 + 7 + 1 =
14 + 5 + 6 + 2 + 3 =
9 + 6 + 6 + 9 =
13 + 10 + 2 =
1 + 9 + 22 =
5 + 15 + 15 =
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