Question

二千零一乘二千分之一千九百九十？

Answer 1

解：二千零一乘二千分之一千九百九十等于（ 3981990/2000 ），【即等于1990.995】
∵已知需求出二千零一乘二千分之一千九百九十等于多少
∴二千零一乘二千分之一千九百九十
= 2001 × 1990/2000
= （2000 + 1）× 1990/2000
= 2000 × 1990/2000 + 1 × 1990/2000
= 1990 + 1990/2000
= 3980000/2000 + 1990/2000
= 3981990/2000
= 1990.995
答：二千零一乘二千分之一千九百九十等于3981990/2000，【即等于1990.995】

Answer 2

2001×1990/2000
=(2000+1）×1990/2000
=2000×1990/2000+1×1990/2000
=1990+199/200
=1990又199/200