7.2*4.12+4.12
=(7.2+1）×4.12
=8.2×4.12
=33.784
100.8除以1.25
=（100+0.8）÷(5/4)
=100×4/5+0.8×4/5
=80+0.64
=80.64
7.2*4.12+4.12 100.8除以1.25巧算
7.2*4.12+4.12
=(7.2+1）×4.12
=8.2×4.12
=33.784
100.8除以1.25
=（100+0.8）÷(5/4)
=100×4/5+0.8×4/5
=80+0.64
=80.64