Question

十一分之五乘四分之一加十一分之三乘21加十一分之五乘五分之一简便计算

Answer 1

(5/11)*(1/4)+(3/11)*21+(5/11)*(1/5)

=(5/11)*(1/4+1/5)+(3/11)*21

=(5/11)*(9/20)+(3/11)*3*7

=(9/11)*(5/20)+(9/11)*7

=(9/11)(1/4+7)

=(9/11)*(29/4)=261/44