35x14-70+30 简便计算

问题描述:

35x14-70+30 简便计算

=30x14+5*14-70+30
=30*(14+1)
=30*15
=450

=35x2x7-70+30
=7x70-70+30
=70x(7-1)+30
=70x6+30
=450

35x14-70+30
=35x14-35x2+30
=35x(14-2)+30
=35x12+30
=420+30
=450