\(\frac{3}{7}.\frac{9}{26}-\frac{1}{14}.\frac{1}{13}\)

\(=\frac{27}{182}-\frac{1}{182}\)

\(=\frac{1}{7}\)

\(\frac{3}{5}.\frac{13}{46}-\frac{1}{10}.\frac{16}{23}\)

\(=\frac{6}{10}.\frac{13}{46}-\frac{1}{10}.\frac{16}{23}\)

\(=\frac{1}{10}.\frac{78}{46}-\frac{1}{10}.\frac{16}{32}\)

\(=\frac{1}{10}\left(\frac{78}{46}-\frac{32}{46}\right)\)

\(=\frac{1}{10}.1=\frac{1}{10}\)

\(\text{Phần a nên sửa đề thế này :}\) \(\frac{1}{7}.\frac{-3}{8}+\frac{1}{7}.\frac{-13}{8}\)

\(\text{Giải :}\)

\(\frac{1}{7}.\frac{-3}{8}+\frac{1}{7}.\frac{-13}{8}\)

\(=\frac{1}{7}\left(\frac{-3}{8}+\frac{-13}{8}\right)\)

\(=\frac{1}{7}.\left(-2\right)\)

\(=\frac{-2}{7}\)

\(\frac{3}{5}.\frac{13}{46}-\frac{1}{10}.\frac{16}{23}\)

\(=\frac{3}{5}.\left(\frac{1}{46}.13\right)-\frac{1}{10}.\frac{32}{46}\)

\(=\left(\frac{3}{5}.13\right).\frac{1}{46}-\left(\frac{1}{10}.32\right).\frac{1}{46}\)

\(=\frac{39}{5}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)

\(=\frac{78}{10}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)

\(=\left(\frac{78}{10}-\frac{32}{10}\right).\frac{1}{46}\)

\(=\frac{46}{10}.\frac{1}{46}\)

\(=\frac{1}{10}\)

`a)3/5+(-4/9)`

`=3/5-4/9`

`=27/45-20/45`

`=7/45`

`b)3/5+2/5 . 15/8`

`=3/5 + 30/40`

`=3/5+3/4`

`=12/20+15/20`

`=27/20`

`c)7/2 . 8/13 + 8/13 . (-5/2)`

`=8/13 . (7/2 +(-5)/2)`

`=8/13 . 1`

`=8/13`

`d)-5/17 . (-9/23)+9/23 . (-22/17) + 11 9/23`

`=-5/17 . (-9/23) + 9/23 . (-1) . 22/17 + 11 + 9/23`

`=-5/17 . (-9/23) + (-9/23) . 22/17+11+9/23`

`= -9/23 ( -5/17 + 22/17)+11+9/23`

`= - 9/23 . 1+11+9/23`

`=-9/23+11+9/23`

`=(-9/23+9/23)+11`

`=0+11`

`=11`

a: =27/45-20/45=7/45

b: =3/5+30/40

=3/5+3/4

=12/20+15/20

=27/20

c: =8/13(7/2-5/2+1)=8/13*2=16/13

d: =9/23*5/17-9/23*22/17+11+9/23

=-9/23+11+9/23

=11

56666666

a) \(\frac{3}{5}\cdot\frac{13}{46}-\frac{1}{10}\cdot\frac{16}{23}=\frac{39-16}{10\cdot23}=\frac{1}{10}\)

b) \(\frac{3}{7}\cdot\frac{9}{26}-\frac{1}{14}\cdot\frac{1}{13}=\frac{27-1}{14\cdot13}=\frac{2\cdot13}{2\cdot7\cdot13}=\frac{1}{7}\)

\(a.\frac{1}{7}\times\frac{-3}{8}+\frac{-13}{8}==\frac{-3}{56}+\frac{-13}{8}=\frac{-3}{56}+\frac{-91}{56}=\frac{-94}{56}=\frac{-47}{28}\)

\(b.\frac{3}{5}\times\frac{13}{40}-\frac{1}{10}\times\frac{16}{23}=\frac{39}{200}-\frac{8}{115}=\frac{577}{4600}\)

\(c.\left(\frac{-3}{4}+\frac{2}{5}\right):\frac{3}{7}+\left(\frac{3}{5}+\frac{1}{4}\right):\frac{3}{7}\)

\(=\left(\frac{-3}{4}+\frac{2}{5}\right)\times\frac{7}{3}+\left(\frac{3}{5}+\frac{1}{4}\right)\times\frac{7}{3}\)

\(=\frac{7}{3}\times\left(\frac{-3}{4}+\frac{2}{5}+\frac{3}{5}+\frac{1}{4}\right)\)

\(=\frac{7}{3}\times\left[\left(\frac{-3}{4}+\frac{1}{4}\right)+\left(\frac{2}{5}+\frac{3}{5}\right)\right]\)

\(=\frac{7}{3}\times\left(\frac{-2}{4}+1\right)\)

\(=\frac{7}{3}\times\frac{1}{2}\)

\(=\frac{7}{6}\)

\(d.\frac{7}{8}:\left(\frac{2}{9}-\frac{1}{8}\right)+\frac{7}{8}:\left(\frac{1}{6}-\frac{5}{12}\right)\)

\(=\frac{7}{8}:\frac{7}{72}+\frac{7}{8}:\left(\frac{-1}{4}\right)\)

\(=\frac{7}{8}\times\frac{72}{7}+\frac{7}{8}\times-4\)

\(=\frac{7}{8}\times\left(\frac{72}{7}+\left(-4\right)\right)\)

\(=\frac{7}{8}\times\frac{44}{7}\)

\(=\frac{11}{2}\)

a) 20

b) 2

c) 0

d) -1

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a; (-5) + 11 + 17 + (-3)

= - 5 + 11 + 17 - 3

= - (5 + 3) + (11 + 17)

= - 8 + 28

= 20

b; \(\dfrac{17}{8}\) - \(\dfrac{5}{8}\) + \(\dfrac{-7}{8}\) + \(\dfrac{11}{8}\)

=  \(\dfrac{12}{8}\) - \(\dfrac{7}{8}\) + \(\dfrac{11}{8}\)

= \(\dfrac{5}{8}\) + \(\dfrac{11}{8}\)

= \(\dfrac{16}{8}\)

= 2

\(\frac{3}{5}.\frac{13}{46}-\frac{1}{10}.\frac{16}{23}\)

\(=\frac{3}{5}.\left(\frac{1}{46}.13\right)-\frac{1}{10}.\frac{32}{46}\)

\(=\left(\frac{3}{5}.13\right).\frac{1}{46}-\left(\frac{1}{10}.32\right).\frac{1}{46}\)

\(=\frac{39}{5}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)

\(=\frac{78}{10}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)

\(=\left(\frac{78}{10}-\frac{32}{10}\right).\frac{1}{46}\)

\(=\frac{46}{10}.\frac{1}{46}\)

\(=\frac{1}{10}\)

13 - 12 + 11 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

= 1 + 11 - 1 + 1 + 11 - 7 + 1

= 12 - 1 + 1 + 11 - 7 + 1

= 11 + 1 + 11 - 7 + 1 

= 12 + 11 - 7 + 1

= 23 - 7 + 1

= 16 + 1 

=17

BẰNG 13 NHÉ BẠN .TK CHO MÌNH NHA .

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