11分之5乘以20分之1加11分之3乘以2分之1加11分之5乘以5分之1用簡算

題目：

11分之5乘以20分之1加11分之3乘以2分之1加11分之5乘以5分之1用簡算

解答：

5/11*1/20 + 3/11*1/2 + 5/11*1/5
= 5/11*(1/20+1/5) + 3/11*1/2
= 5/11*1/4 + 3/11*1/2
= 5/44 + 6/44
= 11/44
= 1/4
5/11*1/20 + 3/11*1/2 + 5/11*1/5
= 1/44 + 3/22 + 1/11
= 1/44 + 6/44 + 4/44
= 11/44
= 1/4