数学问题:0.7×19又2/9+2又3/4×(-14)+0.7×7/9-3.25×14

问题描述:

数学问题:0.7×19又2/9+2又3/4×(-14)+0.7×7/9-3.25×14

0.7×19又2/9+2又3/4×(-14)+0.7×7/9-3.25×14
=0.7×19又2/9+0.7×7/9-3.25×14 +2又3/4×(-14)
=0.7(19又2/9+7/9)-14(3又1/4+2又3/4)
=0.7×20-14×6
=14(1-6)
=-70