Question

帮我做下这三个题：871-87.21+56又21分之19-12.79+43又21分之2=

Answer 1

=-9.2+7.4+46/5-32/5-4-3

=-9又1/5+7又2/5+46/5-32/5-20/5-15/5

=-46/5+37/5+46/5-32/5-20/5-15/5

=(-46+37+46-32-20-15)/5

=-30/5

=-6

=18-6/(-2)*100/9

=18+100/3

=154/3