跪求这几题简便计算的答案

Question

以下题目都要用简便方法计算。（并且要写过程） 1.4538+3998 2.3.2×10.1 3.2.9+29.9+299.9+2999.9 4.4.5÷0.25 5.七分之十二-（八分之三+七分之五） 6.1-0.225÷0.9-0.75 7.67÷（67+68分之67） 8.（八分之五+二十五分之一）×8+二十五分之十七 8.23分之十六×30+16×23分之16

Answer 1

1.4538+3998=4000+538+4000-2=8000+536=8536 2.3.2×10.1=3.2×（10+0.1）=32+0.32=32.32 3.2.9+29.9+299.9+2999.9=3-0.1+30-0.1+300-0.1+3000-0.1=3333-0.4=3332.6 4.4.5÷0.25=(5-0.5)÷(0.5×0.5)=5÷（0.5×0.5）-0.5÷（0.5×0.5）=20-2=18 5.12/7-(3/8+5/7)=12/7-5/7-3/8=1-3/8=5/8 6.1-0.225÷0.9-0.75=0.25-0.225÷0.9=0.25×(1-0.9÷0.9)=0 7.67÷（67+67/68)=1÷(1+1/68)=1÷(69/68)=68/69 8.(5/8+1/25)×8+17/25=5+8/25+17/25=5+1=6 9.16/23×30+16×16/23=16×[(30+16)/23]=16×2=32

Answer 2

4538+3998 =4538+(4000-2) =4538+4000-2 =8538-2 =8536 3.2×10.1 =3.2×(10+0.1) =3.2×10+3.2×0.1 =32+0.32 =32.32 4.5÷0.25 =(4.5×4)÷(0.25×4) =18÷1 =18 2.9+29.9+299.9+2999.9 =（3-0.1）+（30-0.1）+（300-0.1）+（3000-0.1） =（3+30+300+3000）-（0.1*4） =3333-0.4 =3332.6 1-0.225/0.9-0.75 =1-(9/40)/(9/10)-3/4 =1-9/40*10/9-3/4 =1-1/4-3/4 =1-(1/4+3/4) =1-1 =0 =67/[67×(1+1/68)] =1/(1+1/68) =1/(69/68) =68/69