⑴ 怎样用简便方法计算
 脱式计算
  1、75÷〔138÷(100-54)〕
  2、4/7÷[1/3×(3/5-3/10)]
  3、(4/5+1/4)÷7/3+7/10
  4、32.52-(6+9.728÷3.2)×2.5
  5、 87(58+37)÷(64-9×5)
  6、[(7.1-5.6)×0.9-1.15] ÷2.5
  7、(3.2×1.5+2.5)÷1.6
  8、 7 × 5/49 + 3/14
  9、6 ×( 1/2 + 2/3 )
  10、8 × 4/5 + 8 × 11/5
  简算
  1、24*(1/2+5/8+1/6)
  2、(7/10)/3+(3/10)/(1/3)
  3、8 × 4/5 + 8 × 11/5
  4、7/8 + ( 1/8 + 1/9 )
  5、17/32 – 3/4 × 9/24
  6、3 × 2/9 + 1/3
  7、5/7 × 3/25 + 3/7
  8、3/14 ×× 2/3 + 1/6
  9、1/5 × 2/3 + 5/6
  10、9/22 + 1/11 ÷ 1/2
  解比例
  3/5:x=1/3:2 x=3.6
  3:8=15:x x=40
  x:9=4:3 x=12
  1/4:1/8=x:1/10 x=1/5
  1.25:0.25=x:1.6 x=8
  3/4:x=3:12 x=3
  5:8=40:x x=64
  x:3/4=1/5:2/5 x=3/8
  140:2=x:5 x=350
  6.5:x=3.25:4 x=8
 1,4 x 77+8x99=4x7x11+8x9x11=28x11+72x11=11x(28+72)=11x100=1100
  2,666x333=666x3x111=999x111=(1000-1)x111=111000-111=110889
 朋友,这里给你列出分数简便运算题,
  1.3/7 × 49/9 - 4/3
  2. 8/9 × 15/36 + 1/27
  3. 12× 5/6 – 2/9 ×3
  4. 8× 5/4 + 1/4
  5. 6÷ 3/8 – 3/8 ÷6
  6. 4/7 × 5/9 + 3/7 × 5/9
  7. 5/2 -( 3/2 + 4/5 )
  8. 7/8 + ( 1/8 + 1/9 )
  9. 9 × 5/6 + 5/6
  10. 3/4 × 8/9 - 1/3
  11. 7 × 5/49 + 3/14
  12. 6 ×( 1/2 + 2/3 )
  13. 8 × 4/5 + 8 × 11/5
  14. 31 × 5/6 – 5/6
  15. 9/7 - ( 2/7 – 10/21 )
  16. 5/9 × 18 – 14 × 2/7
  17. 4/5 × 25/16 + 2/3 × 3/4
  18. 14 × 8/7 – 5/6 × 12/15
  19. 17/32 – 3/4 × 9/24
  20. 3 × 2/9 + 1/3
  21. 5/7 × 3/25 + 3/7
  22. 3/14 ×× 2/3 + 1/6
  23. 1/5 × 2/3 + 5/6
  24. 9/22 + 1/11 ÷ 1/2
  25. 5/3 × 11/5 + 4/3
  26. 45 × 2/3 + 1/3 × 15
  27. 7/19 + 12/19 × 5/6
  28. 1/4 + 3/4 ÷ 2/3
  29. 8/7 × 21/16 + 1/2
  30. 101 × 1/5 – 1/5 × 21
  31.50+160÷40 (58+370)÷(64-45)
  32.120-144÷18+35
  33.347+45×2-4160÷52
  34(58+37)÷(64-9×5)
  35.95÷(64-45)
  36.178-145÷5×6+42 420+580-64×21÷28
  37.812-700÷(9+31×11) (136+64)×(65-345÷23)
  38.85+14×(14+208÷26)
  39.(284+16)×(512-8208÷18)
  40.120-36×4÷18+35
  41.(58+37)÷(64-9×5)
  42.(6.8-6.8×0.55)÷8
 1.10-5.4=
  2.4÷20=
  3.5×200=
  4.1.5-0.06=
  5.0.75÷15=
  6.0.4×0.8=
  7.4×0.25=
  8.0.36+1.54=
  9.1.01×99=
  10.420÷35=
  11.25×12=
  12.135÷0.5=
  13.3/4 + 1/4 =
  14.2 + 4/9 =
  15.3 - 2/3 =
  16.3/4 - 1/2=
  17.1/6 + 1/2 -1/6 =
  18.7.5-(2.5+3.8)=
  19.7/8 + 3/8 =
  20.3/10 +1/5 =
  21.4/5 - 7/10 =
  22.2 - 1/6 -1/3 =
  23.0.51÷17=
  24.32.8+19=
  25.5.2÷1.3=
  26.1.6×0.4=
  递等式计算
  1. 3/7 × 49/9 - 4/3
  2. 8/9 × 15/36 + 1/27
  3. 12× 5/6 – 2/9 ×3
  4. 8× 5/4 + 1/4
  5. 6÷ 3/8 – 3/8 ÷6
  6. 4/7 × 5/9 + 3/7 × 5/9
  7. 5/2 -( 3/2 + 4/5 )
  8. 7/8 + ( 1/8 + 1/9 )
  9. 9 × 5/6 + 5/6
  10. 3/4 × 8/9 - 1/3
  11. 7 × 5/49 + 3/14
  12. 6 ×( 1/2 + 2/3 )
  13. 8 × 4/5 + 8 × 11/5
  14. 31 × 5/6 – 5/6
  15. 9/7 - ( 2/7 – 10/21 )
  16. 5/9 × 18 – 14 × 2/7
  17. 4/5 × 25/16 + 2/3 × 3/4
  18. 14 × 8/7 – 5/6 × 12/15
  19. 17/32 – 3/4 × 9/24
  20. 3 × 2/9 + 1/3
  21. 5/7 × 3/25 + 3/7
  22. 3/14 ×× 2/3 + 1/6
  23. 1/5 × 2/3 + 5/6
  24. 9/22 + 1/11 ÷ 1/2
  25. 5/3 × 11/5 + 4/3
  26. 45 × 2/3 + 1/3 × 15
  27. 7/19 + 12/19 × 5/6
  28. 1/4 + 3/4 ÷ 2/3
  29. 8/7 × 21/16 + 1/2
  30. 101 × 1/5 – 1/5 × 21
  31.50+160÷40 (58+370)÷(64-45)
  32.120-144÷18+35
  33.347+45×2-4160÷52
  34(58+37)÷(64-9×5)
  35.95÷(64-45)
  36.178-145÷5×6+42 420+580-64×21÷28
  37.812-700÷(9+31×11) (136+64)×(65-345÷23)
  38.85+14×(14+208÷26)
  39.(284+16)×(512-8208÷18)
  40.120-36×4÷18+35
  41.(58+37)÷(64-9×5)
  42.(6.8-6.8×0.55)÷8.5
  43.0.12× 4.8÷0.12×4.8
  44.(3.2×1.5+2.5)÷1.6 (2)3.2×(1.5+2.5)÷1.6
  45.6-1.6÷4= 5.38+7.85-5.37=
  46.7.2÷0.8-1.2×5= 6-1.19×3-0.43=
  47.6.5×(4.8-1.2×4)= 0.68×1.9+0.32×1.9
  48.10.15-10.75×0.4-5.7
  49.5.8×(3.87-0.13)+4.2×3.74
  50.32.52-(6+9.728÷3.2)×2.5
  51.2÷2.5+2.5÷2
  52.194-64.8÷1.8×0.9
  53.36.72÷4.25×9.9
  54.5180-705×6
  55.24÷2.4-2.5×0.8
  56.(4121+2389)÷7
  57.671×15-974
  58.469×12+1492
  59.405×(3213-3189)
  60.3.416÷(0.016×35)
  61.0.8×[(10-6.76)÷1.2]
  62.19.4×6.1×2.3 5.67×0.2-0.62
  63.18.1×0.92+3.93 0.0430.24+0.875
  64.0.4×0.7×0.25 0.75×102 100-56.23
  65.0.78+5.436+1 4.07×0.86+9.12.5
  简便运算
  1. 1-2+3-4+5-6+7-8+9-10+11-12+................+2003-2004+2005-2006+2007
  =1+(3-2)+(5-4)+.........+(2007-2006)
  =1+(2007-1)/2
  =1005
  2、480+325+75
  =480+(325+75)
  =480+400
  =880
  3、295-128-72
  =295+(128+72)
  =295+200
  =495
  4、43×25×4
  =43×(25×4)
  =43×100
  =4300
  5、102×43
  =(100+2)×43
  =100×43+2×43
  =4300+86
  =4386
  6、9×37+9×63
  =9×(63+37)
  =9×100
  =900
  7.66×38-987÷21 66×38-987÷21
  =2508-987÷21 =2508-47
  =2508-47 =2461
  =2461
  8.1.25*17.6+36.1/0.8+2.36*12.5
  1.25*17.6+36.1/0.8+2.36*12.5
  =(5/4)*17.6+36.1*(5/4)+23.6*(50/4)
  =176/8+361/8+236/8
  =773/8=96.625
  9.7.5*2.3+1.9*2.5
  7.5*2.3+1.9*2.5
  =7.5*(1.9+0.4)+1.9*2.5
  =(7.5+2.5)*1.9+7.5*0.4
  =19+3 =22
  10.2004/2003*2005
  2004/2003*2005
  =(2004/2003)*(2003+2)
  =2004+4008/2003
  11.276*543-267/276+543*275
  276*543-267/276+543*275
  =543*(276+275)-267/276
  =543*551-267/276
  12.2002+2001-2000-1999+1998+1997-1996-1995+……+2+1
  =(2002-2000)+(2001-1999)+(1998-1996)+(1997-1995)+……+(6-4)+(5-3)+2+1
  =2+2+2+2+……+2+2(从3-2002共2000个数,所以有1000个2)+2+1
  =1000×2+2+1
  =2003
  13.1/3+1/15++1/35+1/63+九十1/9
  =1/(1×3)+1/(3×5)+1/(5×7)+1/(7×9)+1/(9×11)
  =1/2×(1-1/3)+1/2×(1/3-1/5)+1/2×(1/5-1/7)+1/2×(1/7-1/9)+1/2×(1/9-1/11)
  =1/2×(1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + 1/9 - 1/11)
  =1/2×(1-1/11)
  =1/2×10/11
  =5/11
  14.0.49÷1.4 1.25×2.5×32 3.6-0.6×2
  15.3.65×10.1 3.6-3.6×0.8 15.2÷0.25÷4
  16.5.6÷3.5 9.6÷0.8÷0.4 4.2×99+4.2
  17.0.89×100.1 146.5-(23+46.5) 17.8÷(1.78×4)
  18.5.83×2+4.27 (45.9-32.7)÷8÷0.125 9.7×99+9.7
  19.4.36×12.5×8 15.6×13.1-15.6-15.6×2.1 0.65×101
  20.27.5×3.7-7.5×3.7 8.54÷2.5÷0.4 3.83×4.56+3.83×5.44
  21.9.9×0.625×101-62.5
  22.9.9×8.6+0.86
  23.0. 46×7.5+0. 46×2. 5
  24.4.6×8.04+6.4×8.04-8.04
  25.5.4×0.15÷0.2+4.6×0.15
  =27*0.15+4.6*0.15
  =(27+4.6)*0.15
  =31.6*0.15
  =4.74
  26.55×10.43+104.3×4.4+104.3×0.1
  =55×10.43+10.43×44+10.43×1
  =(55+44+1)*10.43
  =100*10.43
  =1043
  解方程
  1.5/17-x=1/5
  2.5/9+x=23
  3.6x-x=0.5
  4.x-4/9=2/3
  5.4x+20=3.9
  6.4x+12=50
  7.17+8.3 4x=50-12
  8.4x=38
  9.2.3x-1.02=0.36
  10.24 x=0.6
  11.X-5.7=2.15
  12.15 5X-2X=18
  13.3X+0.7=5
  14.3.5×2= 4.2+x
  15.26×1.5= 2x+10
  16.0.5×16―16×0.2=4x
  17.13 9.25-X=0.403
  18.16.9÷X=0. 3
  19.X÷0.5=2.6
  20.x+13=33
  21.3 - 5x=80
  22.1.8 +6x=54
  23.6.7x -60.3=6.7
  24.9 +4x =40
  25.0.2x-0.4+0.5=3.7
  26.9.4x-0.4x=16.2
  口算(补充):
  17×40=680, 100-63=37, 3.2+1.68=4.88, 2.8×0.4= 1.12
  14-7.4=6.6, 1.92÷0.04=48, 0.32×500=160, 0.65+4.35= 5
  10-5.4=4.6, 4÷20=0.2, 3.5×200=700, 1.5-0.06=1.44
  0.75÷15=0.05, 0.4×0.8=0.32, 4×0.25=1, 0.36+1.54=2
  1.01×99=99.99, 420÷35=12, 25×12=300, 135÷0.5=270
  3/4 + 1/4 =1, 2 + 4/9 =22/9, 3 - 2/3 =7/3, 3/4 - 1/2= 1/4
  1/6 + 1/2 -1/6 =1/2, 7.5-(2.5+3.8)=1.2, 7/8 + 3/8 =5/4
  3/10 +1/5 =1/2, 4/5 - 7/10 =1/10, 2 - 1/6 -1/3 =1.5
  0.51÷17=0.03, 32.8+19=51.8, 5.2÷1.3=4, 1.6×0.4= 0.64
  4.9×0.7=3.43, 1÷5=0.2, 6÷12=0.5, 0.87-0.49=0.38
  还有:
  1.(1+1/2)(1+1/3)(1+1/4)......(1+1/100)
  2.(1-1/2)(1-1/3)(1-1/4)......(1-1/100)
  3.8+2-8+2
  4.25*4/25*4
  5.7.26-(5.26-1.5)
  6.286+198
  7.314-202
  8.526+301
  9.223-99
  10.6.25+3.85-2.125+3.875
  11.9-2456*21
  12.0.5/11.5-4*2.75
  13.1/2×3/5
  14.3.375+5.75+2.25+6.625
  15.1001-9036÷18
  16.3.8×5.25+14.5
  17.2.1*4.3+5.7*2.1
  18.30×1/3
  19.102*45-328
  20.2/3×12
  21.2.8*3.1+17.6/8
  22.3/5×5/6
  23.(50-12.5)/2.5
  24.2/5×1/3
  25.6110*47+639
  26.1/2-1/6
  27.3.5*2.7-52.2/18
  28.1/7×1/5
  29.3.375*0.97+0.97*6.625
  30.25×4/5
  31.6.54+2.4+3.46+0.6
  32.5/6-1/2
  33.95.6*1.8+95.6*8.2
  34.1/2×1/5
  35.600-420/12
  36.344/3.6-5.4*0.25
  37.16/2+30/2+90/6
  38.3001-1998.
  39.5000-105*34
  40.0.15/0.25+0.75*1.2
  41.(1/2+1/3+1/4)*0.24
  42.(25+4)*4
  43.300-4263/21
  44.0.81/0.25+5.96
  45.403÷13×27
  46.1.5×4.2-0.75÷0.25
  47.3.27×4 +3.27×5.7
  48.(1.2+ 1.8)×4.51025-768÷32
  49.0.25×80-0.45÷0.9
  50.1025-768÷32
  51.0.25*2.69*4
  52.2348+275*16
  53.2/9*15/8-1/12*9/5
  54.2.4+2.4*(5.375-3.375)
  55.645-45*12
  56.0.15+1.2/0.24-0.45
  57.3.75-(2.35+0.25/1.25)
  58.76*1/4+23*25/100+0.25
  59.10-2.87-7.13
  60.0.96+9.6*9.9
  61.7.5-5.7*1/3
  62.12.37-3.25-6.75
  63.16*6.8+2.2*16+16
  64.401*19+284
  65.58.7-16.65/3.7
  66.0.4*4.7*2.5+(2.3+5.3)
  67.9.31-1.125-7.875
  68.640+128*45
  69.8.2*1.6-0.336/4.2
  70.400*(0.62+0.08)
  1.5×3.6=( ) 3.7×5.3=( ) 2.3×6=( )
  8.1×3.4=( ) 7.6×4.3=( ) 1.6×5.3=( )
  4.3×7-6.3+5.1=( ) 6.2÷3.1×4.5=( )
  (8.6-1.5+9.4)×9.3=( )(5.3+2.7)÷(3.6+2.5)=( )
  4.5*6=?
  6-4.05=?
  8.4÷0.7=?
  3.67+6.13=?
  0.5*1.2=?
  0.55÷1.1=?
  5.42+7.5*1.6=?
  0.25*1.7*0.4=?
  7.86-4015-2.85=?
  0.125*32*2.5=?
  4.5*6=?
  6-4.05=?
  8.4÷0.7=?
  3.67+6.13=?
  0.5*1.2=?
  0.55÷1.1=?
  5.42+7.5*1.6=?
  0.25*1.7*0.4=?
  7.86-4015-2.85=?
  0.125*32*2.5=?
  4.5*6=?
  6-4.05=?
  8.4÷0.7=?
  3.67+6.13=?
  0.5*1.2=?
  0.55÷1.1=?
  5.42+7.5*1.6=?
  0.25*1.7*0.4=?
  7.86-4015-2.85=?
  0.125*32*2.5=?
 小学六年级数学总复习资料(六) 【简便计算】
  班级: 姓名:
  一、口算下面各题。(23分)
  10-2.65= 0.9×0.08= 528-349= 6+14.4= 24÷0.04=
  12.34-2.3= 0÷3.8= 0.77+0.33= 7÷1.4= 67.5+0.25=7.2÷8×4= 5-1.4-1.6= 400÷125÷8= 1.9×4×0.5=
  80×0.125= 3× = 6 6= 2 -( + )= 10 2=
  3.2×7÷3.2×7= ( - )×12= 187.7×11-187.7= 1- 62.5%=
  二、写出下列每题在简便运算时所运用的定律或性质(12分)
  4 +3.2+5 +6.8 25×(8×0.4)×1.25 7 -(2 - )
  ( ) ( ) ( )
  ( + + )×72 93.5÷3 16÷2.5
  ( ) ( ) ( )
  三、用简便方法计算。(65分)
  1125-997 998+1246+9989 (8700+870+87)÷87
  125×8.8 1.3+4.25+3.7+3.75 17.15-(3.5-2.85)
  3.4×99+3.4 4.8×1.01 0.4×(2.5÷73)
  (1.6+1.6+1.6+1.6)×25 ( + - )÷
  12.3-2.45-5.7-4.55 2 + 0.125×0.25×64
  64.2×87+0.642×1300 78×36+7.8×741-7 17+ 8
  0.125× +0.5 2.42 +4.58 -43
  25÷100 4.25-3 -(2 -1 )
  (1)1.25*17.6+36.1/0.8+2.36*12.5
  1.25*17.6+36.1/0.8+2.36*12.5
  =(5/4)*17.6+36.1*(5/4)+23.6*(50/4)
  =176/8+361/8+236/8
  =773/8=96.625
  (2)7.5*2.3+1.9*2.5
  7.5*2.3+1.9*2.5
  =7.5*(1.9+0.4)+1.9*2.5
  =(7.5+2.5)*1.9+7.5*0.4
  =19+3 =22
  (3)2004/2003*2005
  2004/2003*2005
  =(2004/2003)*(2003+2)
  =2004+4008/2003
  (4)276*543-267/276+543*275
  276*543-267/276+543*275
  =543*(276+275)-267/276
  =543*551-267/276
  (5)17/51+ (68/1+51/2)*17
  17/51+ (68/1+51/2)*17
  后面的做不下去了,好像有一些没有简便方法,不知道你题目有没有抄错,你的68/1中的68是分子还是分母呀?应该是分母都对
  (6)(3.25-0.8*8/5)/(6又4/1-3.5)
  是6又1分之4吗?应该是6又4分之1吧
  1)五十二又二十五分之十一×79.45+159×47.56+七十九又二十分之十一×52.44
  =52.44×79.45+159×47.56+79.55×52.44
  =52.44×(79.45+79.55)+159×47.56
  =52.44×159+159×47.56
  =159×(52.44+47.56)
  =159×100
  =15900
  3)2002+2001-2000-1999+1998+1997-1996-1995+……+2+1
  =(2002-2000)+(2001-1999)+(1998-1996)+(1997-1995)+……+(6-4)+(5-3)+2+1
  =2+2+2+2+……+2+2(从3-2002共2000个数,所以有1000个2)+2+1
  =1000×2+2+1
  =2003
  4,5两题均用到一个转换式1/(A×B)=1/(B-A)×(1/A-1/B)
  如1/15=1/(3×5)=1/(5-3)×(1/3-1/5)=1/2×(2/15)=1/15可验证一下
  4)(1×2分之一)+(2×3分之一)+(3×4分之一)+……+(10×11分之一)
  =1/(1×2)+1/(2×3)+1/(3×4)+……+1/(10×11)
  =(1-1/2)+(1/2 - 1/3)+(1/3 - 1/4)+……+(1/10 - 1/11)
  =1-1/11
  =10/11
  5)三分之一+十五分之一+三十五分之一+六十三分之一+九十九分之一
  =1/(1×3)+1/(3×5)+1/(5×7)+1/(7×9)+1/(9×11)
  =1/2×(1-1/3)+1/2×(1/3-1/5)+1/2×(1/5-1/7)+1/2×(1/7-1/9)+1/2×(1/9-1/11)
  =1/2×(1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + 1/9 - 1/11)
  =1/2×(1-1/11)
  =1/2×10/11
  =5/11
  6)一又二分之一-六分之五+十二分之七-二十分之九+三十分之十一-四十二分之十三+五十六分之十五
  (根据提示,1又1/2=1+1/2,+1/2+1/3=5/6……)
  =(1+1/2)-(1/2+1/3)+(1/3+1/4)-(1/4+1/5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)
  =1+ 1/2 - 1/2 - 1/3 + 1/3 + 1/4 - 1/4 - 1/5 + 1/5 + 1/6 - 1/6 - 1/7 + 1/7 + 1/8
  =1+1/8
  =9/8
 网络查:口算题自动生成的小程序 包你满意
  酒仙狂,希望对你有用
 85858585×99999999÷1010101÷11111111
  =85858585÷1010101×99999999÷11111111
  =85×9
  =85×(10-1)
  =850-85
  =765
 =7.69×[1÷(310/100-309/100]
  =7.69×[1÷(310-309)/100]
  =7.69×(1÷1/100)
  =7.69×100
  =769
 1.30.8÷[14-(9.85+1.07)]
  2.[60-(9.5+28.9)]÷0.18
  3.2.881÷0.43-0.24×3.5
  4.20×[(2.44-1.8)÷0.4+0.15]
  5.28-(3.4+1.25×2.4)
  6.2.55×7.1+2.45×7.1
  7.777×9+1111×3
  8.0.8×[15.5-(3.21+5.79)]
  9.(31.8+3.2×4)÷5
  10.31.5×4÷(6+3)
  11.0.64×25×7.8+2.2
  12 2÷2.5+2.5÷2
  13.194-64.8÷1.8×0.9
  14.36.72÷4.25×9.9
  15.5180-705×6
  16.24÷2.4-2.5×0.8
  17.(4121+2389)÷7
  18.671×15-974
  19.0.8×[7.9-(2+5)]
  20.469×12+1492
  21.405×(3213-3189)
  22.3.416÷(0.016×35)
  23.0.8×[(10-6.76)÷1.2]
  24.10x1.3
  25.0.32x100
  26.24+0.24
  27.3.2x0.6
  28.15-0.15
  29.1.9x0.02
  30.0.4x0.5
  31.1.25x8
  32.2.5x4
  33.0.24x4
  34.200x0.16
  35.49×102-2×49
  36.125×78×8
  37.8.33-2.43-4.57
  38.99×37
  39.6.7-2.63+3.3-3.37
  40.41000÷(41×5)
  41.216+305 25×32 47+236+64
  42.6×(15×9) 402+359 43+78+122+257
  43.25×(26×4) 25×44 354+(229+46)
  44.9.26-4.38-2.62
  45.9.26-(4.38+2.26)
  46.9.26-(4.38-2.74)
  47.125×560
  48.45×71+29×45
  49.13.6×8×125
  50.13.6-4.25-5.75+6.4
  51.18.3-6.25-3.75+12.7
  52.64×101
  希望能采纳!
16-6*0.54+1.66*3.6+1.66=16-6*0.54+1.66*(3.6+1)=16-3.24+7.636=20.396
⑵ 镐庢牱绠楃亩渚胯$畻锛
⑶ 四年级数学下册简便计算题1000道
1、24.6-3.98+5.4-6.02
解析:此题利用加法交换结合律,凑整再计算。步骤如下:
24.6-3.98+5.4-6.02
=(24.6+5.4)-(3.98+6.02)
=30-10
=20

2、27×17/26
解析:此题先用加法分配律,把27转换成(26+1),再利用乘法结合律,使得运算简便。
27×17/26
=(26+1)×17/26
=26×17/26+1×17/26
=17+17/26
=17又17/26
3、528-99
解析:利用凑整法和减法结合律计算,先利用凑整法把99变换为(100-1),再运用a-b-c=a-(b+c)来简便计算,步骤如下:
528-99
=528-(100-1)
=528-100+1
=428+1
=429
4、1.2×2.5+0.8×2.5
解析:运用提取公因数的方法,公式:ac+ab=a(b+c),提取公因数2.5,1.2和0.8相加正好凑整数,使得运算简便。
1.2×2.5+0.8×2.5
=(1.2+0.8)×2.5
=2×2.5
=5
5、2.96×40
解析:此题先利用乘法分配律,把2.96×40转换成29.6x4,再利用乘法结合律来简便计算。
2.96×40
=29.6x4
=(30-0.4)x4
=30×4+0.4×4
=120-1.6
=118.4
⑷ 85×202用简便方法计算
85×202
=85X(200+2)
=85X200+85X2
=17000+170
=17170