能用简便方法计算的要用简便方法计算．87×25×78；（59+23）×95；15÷[（79-23）×65]．

Question

能用简便方法计算的要用简便方法计算． (8)/(7)×25×(7)/(8)；

（(5)/(9)+(2)/(3)）×(9)/(5)；

(1)/(5)÷[（(7)/(9)-(2)/(3)）×(6)/(5)]．

Answer 1

（1）(8)/(7)×25×(7)/(8)
=(8)/(7)×(7)/(8)×25
=1×25
=25；

（2）（(5)/(9)+(2)/(3)）×(9)/(5)
=(5)/(9)×(9)/(5)+(2)/(3)×(9)/(5)
=1+(6)/(5)
=2(1)/(5)；

（3）(1)/(5)÷[（(7)/(9)-(2)/(3)）×(6)/(5)]
=(1)/(5)÷[(1)/(9)×(6)/(5)]
=(1)/(5)÷(2)/(15)
=(3)/(2)．