Question

八分之五乘七分之四加八分之二乘七分之五 简便算法

Answer 1

八分之五乘七分之四加八分之二乘七分之五
=5/7×4/8+2/8×5/7
=5/7×(4/8+2/8)
=5/7×3/4
=15/28