0.86+8.6×9.9＝8.6×0.1+8.6×9.9＝8.6×（0.1+9.9）＝8.6×10＝86
3。35.2×45.6＋45.6×63.8＋45.6=（35.2+63.8+1）*45.6=45605、（0.83+11.7）*0.068=0.85204
