(分数题)(1/5+2/7)×5×7 (“/”为分数线)

问题描述:

(分数题)(1/5+2/7)×5×7 (“/”为分数线)

(1/5+2/7)×5×7=
(1/5+2/7)×(5×7)=
1/5 x(5x7)+2/7 x (5x7)=
1x7+2x5=
7+10=
17