Question

7.2*14.5+17*2.8=？？这道题如何简便运算呢？是简便运算啊

Answer 1

7.2×14.5+17×2.8

=7.2×14.5+17×（10-7.2）

=7.2×14.5+17×10-17×7.2

=170+7.2×（14.5-17）

=170-2.5×7.2

=170-7.2×5/2

=170-18

=152

Answer 2

=14.5*7.2+17*2.8
=14.5*7.2+(14.5+2.5)*2.8
=14.5*7.2+14.5*2.8+2.5*2.8
=14.5*(7.2+2.8)+2.5*2+2.5*0.8
=145+5+2
=152