13乘7 13x2 5。用简便方法计算

2020-12-03 21:24:42 字数 6317 阅读 2167

1楼:漫雨弑天

5.3*48+ 5.3*14+ 6.

2*47 =5.3*(48+ 14)+ 6.2*47 =5.

3*62+6.2*47 =5.3*62+62*4.

7 =62x(5.3+4.7) =62x10 =620 希望帮到你 加油

2楼:漫雨弑天

12.6x7.6x2.

32?1.9?

1.4?2.

9如何用简便计算? 12.6x7.

6x2.32?1.

9?1.4?

2.9 =(12.6÷

4)*(7.6÷1.9)*(2.32÷2.9) =3.15*4*0.8 =10.08

6/13x7/5-6/13x2/5。用简便方法计算。

3楼:匿名用户

利用乘法结合律6/13×(7/5-2/5)=6/13。

4楼:宏哥

=6/13×(7/5-2/5)

=6/13×1

=6/13

11/13x6/19十6/13十8/19简便运算?

5楼:小霞

11/13×6/19+6/13+8/19=284/247=247分之284

=6/13×(11/19+1)+8/19

=6/13×30/19+8/19

=1/19×(180/13+8)

=1/19×(180/13+104/13)

=1/19×284/13

=284/247

=247分之284

扩展资料:

简便计算

是一种特殊的计算,它运用了运算定律与数字的基本性质,从而使计算简便,使一个很复杂的式子变得很容易计算出得数。

1、利用乘法分配律进行简便计算:

简便计算中最常用的方法是乘法分配律。乘法分配律指的是ax(b+c)=axb+axc其中a,b,c是任意实数。相反的,axb+axc=ax(b+c)叫做乘法分配律的逆运用(也叫提取公约数),尤其是a与b互为补数时,这种方法更有用。

也有时用到了加法结合律,比如a+b+c,b和c互为补数,就可以把b和c结合起来,再与a相乘。如将上式中的+变为x,运用乘法结合律也可简便计算

2、利用乘法结合律进行简便计算:

乘法结合律也是做简便运算的一种方法,用字母表示为(a×b)×c=a×(b×c),它的定义(方法)是:三个数相乘,先把前两个数相乘,再和第三个数相乘;或先把后两个数相乘,再和第一个数相乘,积不变。它可以改变乘法运算当中的运算顺序,在日常生活中乘法结合律运用的不是很多,主要是在一些较复杂的运算中起到简便的作用。

3、利用乘法交换律进行简便计算:

乘法交换律用于调换各个数的位置:a×b=b×a

4、利用加法交换律进行简便计算:

加法交换律用于调换各个数的位置:a+b=b+a

5、利用加法结合律进行简便计算:

(a+b)+c=a+(b+c)

6楼:匿名用户

望采纳谢谢。(1)2.5*32*0.125

=(2.5*4)*(8*0.125)

=10*1

=10(2)3.5-7+6.5

=3.5+6.5-7

=3(3)1.2×2.5+0.8×2.5

=2.5(1.2+0.8)

=25(4)8.9×1.25-0.9×1.25

=1.25(8.9-0.9)

=10(5)12.5×7.4×0.8

=12.5×0.8×7.4

=74(6)6.5×9.5+6.5×0.5

=6.5×(

9.5+0.5)

=6.5×10

=65(7)0.35×1.6+0.35×3.4

=0.35*(1.6+3.4)

=0.35*5

=1.75

(8)6.72-3.28-1.72

=6.75-(3.28+1.72)

=6.75-5

=1.75

(9)0.45+6.37+4.55

=0.45+4.55+6.37

=5+6.37

=11.37

(10)28×12.5-12.5×20

=(28-20)*12.5

=8*12.5

=100

(11)23.65-(3.07+3.65)

=23.65-3.65-3.07

=20-3.07

=16.93

(12)(4+0.4×0.25)8×7×1.25

=(4+1)*7*10

=5*7*10

=350

(13)1.65×99+1.65

=1.65*(99+1)

=1.65*100

=165

(14)27.85-(7.85+3.4)

=27.85-7.85+3.4

=20+3.4

=23.4

(15)48×1.25+50×1.25×0.2×8

7.8×9.9+0.78

=7.8*(9.9+0.1)

=7.8*10

=78(16)4.8×46+4.8×54

=(46+54)*4.8

=100*4.8

=480

(17)673-327-173

=673-(327+173)

=673-500

=173

(18)4.44*2.5

=1.11*(4*2.5)

=1.11*10

=11.1

(19)3.5÷1.4

=(3.5÷0.7)÷(1.4÷0.7)

=5÷2

=2.5

(20)1+2+3+4+5......+99+100

=(1+99)+(2+98)+(3+97)+......+(49+51)+50

=(100÷2-1)*100+50

=4900+50

=4950⑴运用加法交换律进行简便计算。

0.88+5.6+0.12 1.78+3.5+0.22 5.6+2.08+14.4

=0.88+0.12+5.6 =1.78+0.22+3.5 =5.6+14.4+2.08

=1+5.6 =2+3.5 =20+2.08

=6.6 =5.5 =22.08

⑵运用加法结合律进行简便计算

2.3+(0.56+4.7) 28.6+0.54+0.46+1.4 5.82+4.56+5.44

=(2.3+4.7)+0.56 =(28.6+1.4)+(0.54+0.46) =5.82+(4.56+5.44)

=7+0.56 =30+1 =5.82+10

=7.56 =31 =15.82

⑶、运用乘法交换律进行简便计算。

25×0.37×0.4 7.5×0.39×4 6.5×1.1×4 1.25×3.9×0.8

=25×0.4×0.37 =7.5×4×0.39 =6.5×4×1.1 =1.25×0.8×3.9

=10×0.37 =30×0.39 =26×1.1 =1×3.9

=3.7 =11.7 =28.6 =3.9

⑷、运用乘法结合律进行简便计算。

1.9×7.5×8 6.2×0.8×2.5 4.3×1.5×6 4.1×3.5×2

=1.9×(7.5×8) =6.2×(0.8×2.5) =4.3×(1.5×6) =4.1×(3.5×2)

=1.9×60 =6.2×2 =4.3×9 =4.1×7

=114 =12.4 =38.7 =28.7

⑸、运用乘法分配律的加法进行简算。

13.6×4.6+4.6×6.4 0.72×23+77×0.72 2.6×32+32×2.4

=(13.6+6.4)×4.6 =(23+77)×0.72 =(2.6+2.4) ×32

=20×6.4 =100×0.72 =5×32

=128 =72 =160

⑹、运用乘法分配律的减法进行简算。

12×5.9-5.9×2 4.6×2.5-2.5×0.6 101×9.7-9.7

=(12-2) ×5.9 =(4.6-0.6)×2.5 =(101-1)×9.7

=(12-2) ×5.9 =(4.6-0.6)×2.5 =(101-1)×9.7

=10×5.9 =4×2.5 =100×9.7

=59 =10 =970

⑺、运用减法的运算规律进行简便计算。

1.8-0.45-0.55 54.4-4.6-5.4 35.6-0.13-0.47

=1.8-(0.45+0.55) =54.4-(4.6+5.4) =35.6-(0.13+0.47)

=1.8-1 =54.4-10 =35.6-0.6

=0.8 =44.4 =35

⑻、运用除法的运算规律进行简便计算。

4.5÷4÷7.5 14.8÷1.25÷8 18.5÷4÷1.25 5.4÷4÷0.45

=4.5÷(4×7.5) =14.8÷(1.25×8) =18.5÷(4×1.25) =5.4÷(4×0.45)

=4.5÷30 =14.8÷10 =18.5÷5 =5.4÷0.18

=0.15 =1.48 =3.7 =30

⑼综合运用各种运算定律进行简算。

2.54+2.46+0.44+0.54 10.7×0.4-6.7×0.4 0.5×3.2×1.25

=(2.54+2.46)+(0.44+0.54) =(10.7-6.7)×0.4 =(0.5×4)×(0.8×1.25)

=5+1 =4×0.4 =2×1

=6 =1.6 =2

89.7+5.8-9.7+4.2 99×0.38+0.38 360÷(18×0.4)

=(89.7-9.7)+(5.8+4.2) =(99+1) ×0.38 =360÷18÷0.4

=80+10 =100×0.38 =20÷0. 4

=90 =38 =50

4.8×12.5 2.5×1.6×12.5 3.2×102

=0.6×(8×12.5) =(2.5×0.2)×(8×12.5) =3.2×(100+2)

=0.6×100 =0.5×100 =3.2×100+3.2×2

=60 =50 =320+6.4

=326.4

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