How to say "multiplication" in Japanese

• 掛け算かけざんJLPT N2approx.Common
  nounThe arithmetic sense: multiplying numbers, as taught in school mathematics. If you mean the operation of multiplication itself, this is the word you want.
  子供こどもたちは掛け算かけざんを暗記あんきしている。↗

  The children are learning the multiplication tables by heart.
• 相乗そうじょうCommon
  noun, suru verbCovers multiplication in a mathematical or abstract sense, but its gloss also points to synergism, so it often suggests mutually reinforcing effects rather than plain calculation.
• 増殖ぞうしょくCommon
  noun, suru verb, transitive verb, intransitive verbMultiplication as increase in number: cells, bacteria or other things proliferating. It conveys rapid, multiplying growth, and is not used for arithmetic.
• 繁殖はんしょくJLPT N1approx.Common
  noun, suru verb, intransitive verbMultiplication through breeding and reproduction of living things; the emphasis is on propagation of organisms rather than on increase of numbers, and never on arithmetic.
  ８月がつ下旬げじゅんに彼かれらは繁殖はんしょくのために長ながい旅たびに出発しゅっぱつします。↗

  In late August, they set off on a long journey for breeding.

Use 「掛け算」 for arithmetic, 増殖 for cells or organisms multiplying, 繁殖 for breeding and reproduction, and 相乗 mainly for synergistic, mutually reinforcing multiplication.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 掛け算かけざんmultiplication
• 相乗そうじょうmultiplication
• 増殖ぞうしょくincrease
• 繁殖はんしょくbreeding
• 乗算じょうざんmultiplication
• 乗法じょうほうmultiplication
• 逓倍ていばいmultiplication (e.g. of frequencies)
• 乗じょうmultiplication