29X102-29X2简便算法
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12.5x79+12.5x2-12.5=12.5x(79+2-1)=12.5x80=1000
71*24+76*29=71*24+24*29+52*29=(71+29)*24+52*30-52=100*24+1560-52=2400+1560-52=3960-52=3908
55*29+55=55*(29+1)=55*30=1650
⑴31X102=31×(100+2)=31×100+31×2=3100+62=3162⑵9.9+99.9+999.9+0.3=9.9+99.9+999.9+(0.1+0.1+0.1)=(9.9+0.1
每个加数都写成(1-一个数)原式=6-(1/2+1/6+1/12+...1/42)1/6=1/2-1/31/12=1/3-1/4...1/42=1/6-1/7
原式=31+34+37+41+43-25-27-29-31-3331-31+34-33+37-27+41-29+43-25(提取分组31-3134-3337-2741-2943-25所得结果分别相加)
3.9x1.4÷0.350.13*1020.5*2.33*49.07-22.78÷34=3.9*2*0.7÷0.7÷0.5=0.13*(100+2)=0.5*4*2.33=9.07-0.67=7.8÷
解题思路:根据乘法交换律、乘法分配律,可求。解题过程:varSWOC={};SWOC.tip=false;try{SWOCX2.OpenFile("http://dayi.prcedu.com/inc
2/5x4+1/5x2/13+2/5x12/13=2/5x4+2/5x1/13+2/5x12/13=2/5x(4+1/13+12/13)=2因为1/5x2/13=2/5x1/13
(2980/81)*(-9)=(30-1/81)×{-9)=-270+1/9=-2698/9
(6-5.96)x2.5+0.83=0.04x2.5+0.83=0.1+0.83=0.93
0.485*100+0.485*2-48.5=0.97
3.8x2.7+38x0.73=3.8x2.7+(3.8x10)x0.73=3.8x2.7+3.8x(10x0.73)=3.8x2.7+3.8x7.3=3.8x(2.7+7.3)=3.8x10=38
7÷29×1÷4+7÷4×3÷29=(1+3)×7÷4÷29=7/29
x^2-3x+1=0显然x不等于0这样x^2+1=3x两边同除以x有:x+1/x=3再两边平方,有:x^2+1/x^2+2=9所以x^2+(1/x)^2=9-2=7选A
21+22+23+24+25+26+27+28+29=(21+29)+(22+28)+(23+27)+(24+26)+25=50+50+50+50+25=50×4+25=200+25=225
87X64+108X29=87X64+3X36X29=87X64+87X36=87X(64+36)=87x100=8200
=(201-145)*29=56*29=56*(30-1)=1680-56=1624
37*29+37+37+37*70=37*(29+1+70)+37=37*100+37=3700+37=3737再问:=37*(29+70+2)=37*101=3737是不是更简便再答:37*101计