精选小学数学简便运算归类练习2017
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一、运用加法结合律进行简算 (a+b)+c=a+(b+c)
例1、5.76+13.67+4.24+6.33 =(5.76+4.24)+(13.67+6.33) =10+10 =20
例2、37.24+23.79-17.24 =37.24-17.24+23.79 =20+23.79 =43.79
二、运用乘法结合律进行简算：这种题型往往含特殊数字之间相乘 (a×b)×c=a×(b×c) 特殊数字之间相乘：
25×4=100 125×8=1000 25×8=200 125×4=500
例3、 4×3.78×0.25 =4×0.25×3.78 =1×3.78 =3.78
例4、 125×246×0.8 =125×0.8×246 =100×246 =24600
三、利用乘法分配律进行简算: (a+b)×c=a×c+ b×c (a-b)×c=a×c- b×c
做这种题,一定不要急着去算,先要分析各数字之间的特殊关系。也就是先要仔细观察，找到做题的窍门。 例5、(2.5+12.5)×40 =2.5×40+12.5×40 =100+500 =600
例6、3.68×4.79+6.32×4.79
=(3.68+6.32)×4.79 =10×4.79 =47.9
例7. 26.86×25.66-16.86×25.66 =(26.86-16.86) ×25.66 =10×25.66 =256.6
例8、 5.7×99+5.7 = 5.7×(99+1) =5.7×100 =570
四、利用加减乘除把数拆分后再利用乘法分配律进行简算： 例9、34×9.9 =34×(10-0.1) =34×10-34×0.1 =340-3.4 =336.6
例10、 57×101 =57×(100+1) =57×100+57×1 =5757
例11、7.8×1.1 =7.8×(1+0.1) =7.8×1+7.8×0.1 =7.8+0.78 =8.58
例12、25×32 =25×4×8 =100×8 =800
例13、125×0.72 =125×8×0.09 =1000×0.09 =90
例14、87×2/85 =(85+2) ×2/85 =85×2/85+2×2/85 =2+4/85 =2又4/85
五、连减与连除 a-b-c=a-(b+c) a÷b÷c=a÷(b×c) 例15、56.5-3.7-6.3
=56.5-(3.7+6.3) =56.5-10 =46.5
例16、32.6÷0.4÷2.5 =32.6÷(0.4×2.5) =32.6÷1 =32.6
六、需要变形才能进行的简便运算:做这一类题，要先观察，找出规律，然后变形后进行简算。
例16、86.7×0.356+1.33×3.56 =8.67×3.56+1.33×3.56 =(8.56+1.33)×3.56 =10×3.56 =35.6
例17、15.6÷4-5.6×1/4 =15.6×1/4-5.6×1/4 =(15.6-5.6)×1/4 =10×1/4 =2又1/2
例18、16/23×27+16×19/23 =27/23×16+16×19/23 =16×(27/23+19/23) =16×2 =32
30.8÷[14-(9.85+1.07)] [60-(9.5+28.9)]÷0.18 2.881÷0.43-0.24×3.5 20×[(2.44-1.8)÷0.4+0.15] 28-(3.4+1.25×2.4) 2.55×7.1+2.45×7.1 777×9+1111×3
0.8×[15.5-(3.21+5.79)] (31.8+3.2×4)÷5 31.5×4÷(6+3) 0.64×25×7.8+2.2 2÷2.5+2.5÷2 194-64.8÷1.8×0.9 36.72÷4.25×9.9 5180-705×6 24÷2.4-2.5×0.8 (4121+2389)÷7 671×15-974 0.8×[7.9-(2+5)]
469×12+1492 405×(3213-3189) 3.416÷(0.016×35) 0.8×[(10-6.76)÷1.2] 10x1.3
0.32x100
24+0.24
3.2x0.6
15-0.15
1.9x0.02
0.4x0.5
1.25x8
2.5x4
0.24x4
200x0.16
0.6x0.1
