递等式计算简便方法(递等式计算.能简便的用简便方法计算199*101273*165)
1.【递等式计算.（能简便的用简便方法计算）（1）99*101(2)73*165
(1)99*101=99*(100+1)=99*100+99*1=9900+99=9999;(2)73*165-73*66+73=73*(165-66+1)=73*100=7300;(3)25*64*125*13=25*(8*8)*125*13=(25*8)*(8*125)*13=200*1000*13=200000*13=2600000;(4)9670-(129-73)*24=9670-56*24=9670-1344=8326;(5)(67*25+33*25)*40=[(67+33)*25]*40=[100*25]*40=2500*40=100000;(6)450÷[（393-388）*(6+4)]=450÷[5*10]=450÷50=9.。
2.递等式计算
1又5/7+2/3+3又1/3+2又2/7
=1+5/7+2/3+3+1/3+2+2/7
=1+3+2+5/7+2/7+2/3+1/3
=6+1+1
=8
1又1/2-3/4+5/6
=1+1/2-3/4+5/6
=1+6/12-9/12+10/12
=1+7/12
=1又7/12
9又3/5-2又1/6-3又5/6+2又2/5
=9+3/5-2-1/6-3-5/6+2+2/5
=9-2-3+2+3/5+2/5-(1/6+5/6)
=6+1-1
=6
3/7+7/8+4/7-1/8
=3/7+4/7+7/8-1/8
=1+6/8
=1+3/4
=1又3/4
2又3/5-(2/9+3/5)
=2+3/5-2/9-3/5
=2-2/9+3/5-3/5
=1+9/9-2/9+0
=1+7/9
=1又7/9
2.8+1/2-1.6
=2.8-1.6+1/2
=1.2+0.5
=1.7
3.递等式计算,能简便的要简便方法计算
12000÷（120-40*2）+20
=12000÷（120-80）+20
=12000÷40+20
=300+20
=320
25*11*24
=(25*4)*(11*6)
=100*66
=6600
101*99-99
=(101-1)*99
=100*99
=9900
11000÷125*8
=(11000*8)÷（125*8）*8
=88000÷1000*8
=88*8
=704
(54*21+45*21)÷33
=(54+45)*21÷33
=99*21÷33
=(99÷33)*21
=3*21
=63
335-287+265-113
=(335+265)-(287+113)
=600-400
=200
4.递等式计算
解1:
7/31*13+13/31*20
=7*13/31+13*20/31
=(13/31)(7+20)
=(13/31)*27
=13*27/31
=351/31
解2:
(2/11)*(11+44)+(3/5)÷1/25
=(2/11)*55+(3/5)*25
=2*5+3*5
=10+15
=25
解3:
(6又1/2-3又3/4)÷（13+11又1/5）
=(13/2-15/4)÷（13+56/5）
=(26/4-15/4)÷（65/5+56/5）
=(11/4)÷（121/5）
=(11/4)*(5/121)
=(1/4)*(5/11)
=5/44
解4:
3.3*[38+3又1/5÷（1又3/4-0.15）]
=(33/10)*[38+(16/5)÷（7/4-3/20）]
=(33/10)*[38+(16/5)÷（35/20-3/20）]
=(33/10)*[38+(16/5)÷（8/5）]
=(33/10)*[38+(16/5)*(5/8)]
=(33/10)*(38+2)
=(33/10)*40
=33*4
=132
5.递等式计算（能简便的简便）
(1)5/8÷5+1/5*1/8=5/8*1/5+1/5*1/8=1/5*(5/8+1/8)=1/5*6/8=1/5*3/4=3/20.(2)(2/7+5/14)÷1/7=(2/7+5/14)*7=2+5/2=4又1/2.(3)8/13*1/9÷4/39=8/13*1/9*39/4=2/3.(4)6分之1*3分支÷（5分之4-15分之7）(3分之几？)（5）4-(1/4+3/8)÷1/4=4-(1/4+3/8)*4=4-(1+3/2)=4-1-3/2=3-3/2=1又1/2.(1)设全长为x，列方程：（3/7）x=420x=980(2)设水蹈有x吨，列方程：60÷（1-1/8）=x,x=480/7。
