解:(1)40×

,
=(39+1)×

,
=39×

+1×

,
=38+

,
=38

;
(2)

+

+

+

+

,
=

+

+

+

+

,
=(

)-(

)-

=1-

,
=

;
(3)25×(

+

)×30,
=(25×

+25×

)×30,
=(1+

)×30,
=30+30×

,
=30+25,
=55.
分析:(1)将40写成39与1的和,再运用乘法分配律计算;
(2)因为

+

+

+

+

=

+

+

+

+

=(

)-(

)-

,计算即可;
(3)运用乘法分配律计算即可.
点评:解决本题要细心分析数据,选择适合的方法解答.