いい加減にしなさい[iikagennishinasai] shape up!
一律減反[ichiritsugentan] reduction in area of rice under cultivation
塩加減[shiokagen] seasoning (with salt)
加減[kagen] addition and subtraction
加減乗除[kagenjoujo] the four arithmetical operations (addition, subtraction, multiplication, division)

加減抵抗器[kagenteikouki] rheostat
火加減[hikagen] condition of fire
経費削減[keihisakugen] cost reduction
軽減[keigen] abatement
激減[gekigen] dropping sharply

アナログ計算機[anarogukeisanki] analog computer
シフト演算機構[shifutoenzankikou] shift arithmetic unit
暗算[anzan] mental arithmetic
違算[isan] miscalculation
一般命令演算機構[ippanmeireienzankikou] general instruction unit (computer)

運算[unzan] mathematical operation
演算[enzan] (mathematical) operation
演算機[enzanki] processor (as in computer chip)
演算子[enzanshi] operator
演算手順[enzantejun] algorithm