4/7 × 5/9 + 3/7 × 5/9 简算,

问题描述:

4/7 × 5/9 + 3/7 × 5/9 简算,

4/7 × 5/9 + 3/7 × 5/9
=(4/7+3/7)x5/9
=1x5/9
=5/9