1.000.000×3.5%×9/12
= 1000000 × 3.5 × (1/100) × 9 × (1/12)
すべて掛け算なので交換則で
= 3.5 × 9 × (1/12) × 1000000 × (1/100) 指数は後回し
= (3.5 × 9)/12 × 10000
= (3.5×3)/4 × 10000
= 10.5/4 × 10000 いきなり4で割るのは面倒なので
= 5.25/2 × 10000
= 2.625 × 10000
= 26250
暗算でするなら
= 3.5 × 9/12 × 10⁽⁶⁻²)
= 3.5 × 3/4 × 10⁴
= 10.5/4 × 10⁴
= 5.25/2 × 10⁴
= 2.625 × 10⁴