What is Addition?

Arithmetic · Axiom Academy

Combining quantities into a single total — the first operation of arithmetic. Start with the simplest picture of addition: one group of 3 and another group of 2. Bringing them together into a single group is exactly what the plus sign means. Every addition sentence has named parts. The numbers being combined are the addends ; the result is the sum . A quantity being combined. In 3 + 2 = 5, both 3 and 2 are addends. The symbol for combining. Read it as "plus" or "and". States that both sides name the same quantity. The total after combining. In 3 + 2 = 5, the sum is 5. "3 + 2 = 5" is read "three plus two equals five." In context: 3 items and 2 items make 5 items. The objects change; the arithmetic doesn't. Each situation below is the same operation. A bookshelf holds 4 novels and you shelve 3 more: 4 + 3 = 7 novels. 5 people are in the room and 2 more join: 5 + 2 = 7 people. You set aside 6 one week and 4 the next: 6 + 4 = 10. Addition is the foundation the rest of arithmetic is built on. Next come the addition facts, then mental strategies — making ten, doubles — that make addition fast without counting. Scroll up to revisit any step.

This is the written version of the interactive lesson above. See the full Arithmetic course.