Calculation
noun, verbal noun
When you measure and then calculate something, you are making a calculation. For example, you measure the length of a frog, then you calculate how many frogs you'd need to reach the moon. What is that? A calculation, of course.
けいさん
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
彼は計算が速いです。
He is quick at calculations.
この計算、合ってる？
Is this calculation correct?
あの女は計算高いことで有名です。
That woman is famous for being calculated.