暗あん算ざん

あ

ん

ざ

ん

JLPTN1Freq.FrequencyTop 50,000

暗算する · noun or participle which takes 'suru'

Meanings

mental arithmetic; mental calculation

Doing arithmetic in one's head without using a calculator, abacus, or writing. Often used with する to mean 'do mental arithmetic'.

〈数かず〉を暗あん算ざんするto calculate a number mentally
彼かれは買かい物ものの合ごう計けいを暗あん算ざんした。
He calculated the total of his shopping in his head.
暗あん算ざんが得とく意いだ／苦にが手てだto be good at / bad at mental arithmetic
妹いもうとは暗あん算ざんが得とく意いで、電でん卓たくなしでも速はやく計けい算さんできる。
My younger sister is good at mental arithmetic and can calculate fast even without a calculator.
暗あん算ざんで〈事こと〉を計けい算さんするto work something out by mental calculation
レジで暗あん算ざんで割わり引びき後ごの値ね段だんを計けい算さんした。
At the register, I worked out the discounted price by mental arithmetic.

計けい算さんN4
計算 is the general word for any kind of calculation (mental, written, or with a device), while 暗算 specifically means doing the calculation in one's head.
珠しゅ算ざん
珠算 is calculation performed using a physical abacus, while 暗算 is calculation done purely in one's head without any tool.

筆ひっ算さん
筆算 means calculating on paper with written figures, the opposite method to 暗算, which is done entirely in one's head.

暗あん殺さつN1
暗殺 (あんさつ) means 'assassination', while 暗算 (あんざん) means 'mental arithmetic'; the words share the first kanji and a similar sound but are unrelated in meaning.

Compound of 暗 (an, 'in the dark; mental') and 算 (san, 'calculation'). The kanji 暗 suggests doing something internally or without external aids.