Mathematics · Glossary

What is Addition?

Also known as: sum

Definition 2.1 Primary & Middle School Mathematics · Chapter 2 — Addition: First Steps

Adding means putting together and counting everything. We write

3+2=53 + 2 = 5

and read: “three plus two equals five”. The answer of an addition is called the sum.

An addition in pictures: the two groups together make one group of five.
An addition in pictures: the two groups together make one group of five.

Examples

Example 2.2 (The order does not matter)

2+32 + 3 and 3+23 + 2 put together the same marbles: both make 55. To compute 2+92 + 9, it is faster to start from the bigger number: say “nine”, then count on two — “ten, eleven”. So 2+9=112 + 9 = 11.

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