Addition
noun
Remember how 足す means "to add?" Add calculate to that and you'll have addition! It's the type of calculation you're doing when you add.
This is the kun'yomi reading for 足 and the on'yomi for 算. And the さん reading is rendaku'd into ざん. This is the same for all the math-ish words (addition, subtraction, multiplication, and division), so try to remember that, because you'll see it again!
足し算を学ぶ
to learn addition
足し算を教える
to teach addition
足し算をする
to do addition
私の兄は、足し算が上手で早いです。
My brother is good and fast at adding.
この足し算の答えは正しくありません。
The answer to this addition is incorrect.
次回の数学のクラスで足し算のテストがあります。
There will be a test for additions in the next math class.