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12 tháng 3 2022

=21/11 nha

14 tháng 7 2015

( 7/20 + 11/15 - 15/12 ) : ( 11/20 - 26/45 )

= -1/6 : -1/36

= -5/36

11 tháng 4 2019

a/b là phân số nha

11 tháng 4 2019

\(\left(\frac{7}{20}+\frac{11}{15}-\frac{15}{12}\right):\left(\frac{11}{20}-\frac{26}{45}\right)\)

\(=\left(\frac{21}{60}+\frac{44}{60}-\frac{75}{60}\right):\left(\frac{99}{180}-\frac{104}{180}\right)\)

\(=-\frac{1}{6}:\frac{-1}{36}\)

\(=\frac{-36}{-6}\)

\(=6\)

13 tháng 3 2022

21/11

13 tháng 3 2022

=7/15:11/45

=7/15×45/11

=7/1×3/11

=21/11

1.

\(\left(572\cdot7+266\right)\cdot\left(366\cdot9-168\cdot18\right)\cdot\left(346\cdot6-348\right)\)

\(=\left(286\cdot7\cdot2+133\cdot2\right)\cdot\left(366\cdot9-168\cdot2\cdot9\right)\cdot\left(173\cdot6\cdot2-174\cdot2\right)\)

\(=\left(2002\cdot2+133\cdot2\right)\cdot\left(366\cdot9-336\cdot9\right)\cdot\left(1038\cdot2-174\cdot2\right)\)

\(=\left[2\cdot\left(2002+133\right)\right]\cdot\left[9\cdot\left(366-336\right)\right]\cdot\left[2\cdot\left(1038-174\right)\right]\)

\(=2\cdot2135\cdot9\cdot30\cdot2\cdot864\)

\(=4270\cdot9\cdot30\cdot2\cdot864\)

\(=\left(4270\cdot30\right)\cdot9\cdot2\cdot864\)

\(=\left(427\cdot10\right)\cdot\left(3\cdot10\right)\cdot9\cdot2\cdot864\)

\(=\left(427\cdot3\right)\cdot\left(10\cdot10\right)\cdot9\cdot2\cdot864\)

\(=1281\cdot100\cdot9\cdot2\cdot864\)

\(=\left(1281\cdot100\right)\cdot\left(9\cdot2\cdot864\right)\)

\(=\left(1281\cdot100\right)\cdot15552\)

\(=\left(1281\cdot15552\right)\cdot100\)

\(=19922112\cdot100\)

\(=1992211200\)

2.

\(\left(1+3+5+7+...+97+9\right)\cdot\left(45\cdot3-15\cdot2-45\right)\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left(15\cdot3\cdot3-15\cdot2-15\cdot3\right)\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left[15\cdot\left(3\cdot3\right)-15\cdot2-15\cdot3\right]\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left(15\cdot9-15\cdot2-15\cdot3\right)\)

\(=\left(1+3+5+7+...+97+9\right)\cdot\left[15\cdot\left(9-2-3\right)\right]\)

\(=\left(1+3+5+7+...+97+9\right)\cdot15\cdot4\)

\(=\left[\left(1+3+5+7+...+97\right)+9\right]\cdot\left(15\cdot4\right)\)

Trong \(\left(1+3+5+7+...+97\right)\) có số số hạng là:

        \(\left(97-1\right)\div2+1=49\) ( số hạng )

\(\Rightarrow\left[\left(1+3+5+7+...+97\right)+9\right]\cdot\left(15\cdot4\right)\)

\(=\left[\left(97+1\right)\cdot49\div2\right]\cdot\left(15\cdot4\right)\)

\(=2401\cdot60\)

\(=\left(2401\cdot6\right)\cdot10\)

\(=14406\cdot10\)

\(=144060\)

3.

\(\left(180\div15-132\div11\right)\cdot\left(57869-297\div11\cdot108\right)\)

\(=\left(12-12\right)\cdot\left(57869-297\div11\cdot108\right)\)

\(=0\cdot\left(57869-297\div11\cdot108\right)\)

\(=0\)

Sửa lại bài 2; dòng 11 ( từ đề bài bài 2 ):

\(=\left\{\left[\left(97+1\right)\cdot49\div2\right]+9\right\}\cdot\left(15\cdot4\right)\)

\(=\left(2401+9\right)\cdot\left(15\cdot4\right)\)
\(=2410\cdot\left(15\cdot4\right)\)

\(=2410\cdot60\)

\(=\left(241\cdot10\right)\cdot\left(6\cdot10\right)\)

\(=\left(241\cdot6\right)\cdot\left(10\cdot10\right)\)

\(=1446\cdot10\)

\(=14460\)

3 tháng 3 2023

`4/7+4`

`=4/7+4/1`

`=4/7+28/7`

`=32/7`

__

`3+6/11`

`=33/11+6/11`

`=39/11`

__

`3-5/7`

`=3/1-5/7`

`=21/7-5/7`

`=16/7`

__

`21/9-2`

`=21/9-18/9`

`=3/9`

`=1/3`

__

`15/24+2`

`=15/24+48/24`

`=63/24`

`=21/16`

__

`63/45-20/25`

`=63/45-4/5`

`=63/45-36/45`

`=27/45`

`=9/15`

__

`3/4-2/8`

`=3/4-1/4`

`=2/4`

__

`6/7-5/8`

`=48/56-35/56`

`=13/56`

__

`37/45-5/9`

`=37/45-25/45`

`=12/45`

`=4/15`

__

`46/39-11/13`

`=46/39-33/39`

`=13/39`

`=1/2`

__

`5/12+3/4+1/3`

`=5/12+9/12+4/12`

`=14/12+4/12`

`=18/12`

`=3/2`

__

`1/2+3/7+11/14`

`=7/14+6/14+11/14`

`=13/14+11/14`

`=24/14`

`=12/7`

__

`7/10-(1/5+1/4)`

`=7/10-(4/20+5/20)`

`=7/10-9/20`

`=14/20-9/20`

`=5/20`

`=1/4`

__

`15/4-2/3-3/4`

`=(15/4-3/4)-2/3`

`=12/4-2/3`

`=3-2/3`

`=9/3-2/3`

`=7/3`

26 tháng 1 2016

dễ mà bạn, dựa vào kiến thức dẫ học kết hợp với việc bạn làm nháp và dùng máy tính để hỗ trợ thì chắc chắc những bài trên chỉ là chuyện nhỏ

26 tháng 1 2016

haidangbb làm ra lun đi

28 tháng 1 2022

4 : 9 = \(\dfrac{4}{9}\)                         8 : 11 =\(\dfrac{8}{11}\)             7 : 15 =\(\dfrac{7}{15}\)

15 : 5 =  \(\dfrac{15}{5}=\dfrac{3}{1}\)                     63 : 21 =\(\dfrac{63}{21}\)           45 : 9 =\(\dfrac{45}{9}=\dfrac{5}{1}\)

6 : 18 =  \(\dfrac{6}{18}=\dfrac{1}{3}\)                       144 :  24 =\(\dfrac{244}{24}\)       7 =\(\dfrac{7}{1}\)

15 =  \(\dfrac{15}{1}\)                            10 = \(\dfrac{10}{1}\)                0 =\(\dfrac{0}{1}\)

\(4:9=\dfrac{4}{9};15:5=\dfrac{15}{5}=3;6:18=\dfrac{6}{18}=\dfrac{1}{3}\\ 15=\dfrac{15}{1};8:11=\dfrac{8}{11};63:21=\dfrac{63}{21}=3;144:24=\dfrac{144}{24};10=\dfrac{10}{1}\\ 7:15=\dfrac{7}{15};45:9=\dfrac{45}{9}=5;7=\dfrac{7}{1};0=0\)

7 tháng 3 2016

???????????????????????????????????????????????????????????????????????

21 tháng 4 2017

\(A=\left(\dfrac{5}{12}.\dfrac{21}{15}\right):\dfrac{1}{4}\)

\(=\dfrac{7}{12}:\dfrac{1}{4}\)

\(=\dfrac{28}{12}=\dfrac{7}{3}\)

\(B=\left(\dfrac{2}{7}:\dfrac{5}{4}\right).\left(\dfrac{5}{8}:2\right)\)

\(=\dfrac{8}{35}.\left(\dfrac{5}{8}:2\right)\)

\(=\dfrac{8}{35}.\dfrac{5}{16}\)

\(=\dfrac{1}{14}\)

\(C=\left(\dfrac{11}{15}.\dfrac{35}{44}\right).\left(\dfrac{1}{7}.\dfrac{4}{13}\right)\)

\(=\dfrac{7}{12}.\left(\dfrac{1}{7}.\dfrac{4}{13}\right)\)

\(=\dfrac{7}{12}.\left(\dfrac{1}{7}.\dfrac{4}{13}\right)\)

\(=\dfrac{7}{12}.\dfrac{4}{91}\)

\(=\dfrac{1}{39}\)

\(D=\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)

\(=\left(\dfrac{13}{12}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)

\(=\dfrac{-1}{6}:\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)

\(=\dfrac{-1}{6}:\dfrac{-1}{36}\)

\(=6\)

25 tháng 1 2018

21.35-3.25.7

= 21.35-21.25

= 21.(35-25)

= 21. 10

=210

77 - 11.( 30+7)

= 11.7 -11.30 -11.7

= 11.7-11.7 -11.30

= -11.30

= -330

25 tháng 1 2018

21.35-3.25.7=210

77-11(30+7)=-330

85(35-27)-35(85-27)=-1350

47(45-15)-47(45+15)=-2820