4.6*301-4.6 =4.6*(301-1)=4.6*300= 1380
0.9*12.5 =(0.8+0.1)*12.5=10+1.25=11.25
1.076*3.4+10.76*0.66=1.079*(3.4+6.6)=10.76
9.24/0.4/0.25=9.24*2.5*4=92.4
（4.8+3.6+2.4）/0.6=4.8/0.6+6/0.6=8+10=18
0.12*86.4+1.136*12=0.12*(86.4+113.6)=0.12*200=24
0.7777*0.7+0.1111*2.1=0.7777*(0.7+0.3)=0.7777
99*2.2+2.2=2.2*(99+1)=220