Câu 1:

a. $3\frac{2}{3}+2\frac{1}{2}=(3+2)+(\frac{2}{3}+\frac{1}{2})=5+\frac{7}{6}=6+\frac{1}{6}=6\frac{1}{6}$

b. \(2\frac{1}{2}\times 3\frac{2}{5}=\frac{5}{2}\times \frac{17}{5}=\frac{17}{2}\)

c.

\(3\frac{1}{3}: 4\frac{1}{4}=\frac{10}{3}: \frac{17}{4}=\frac{40}{51}\)

d.

\(3\frac{1}{2}+4\frac{5}{7}-5\frac{5}{14}=(3+4-5)+(\frac{1}{2}+\frac{5}{7}-\frac{5}{14})=2+\frac{6}{7}=2\frac{6}{7}\)

Câu 2:

a. $x\times \frac{2}{7}=\frac{6}{11}$

$x=\frac{6}{11}: \frac{2}{7}=\frac{21}{11}$

b. $x: \frac{3}{2}=\frac{1}{4}$

$x=\frac{1}{4}\times \frac{3}{2}=\frac{3}{8}$

Câu 3:

Coi số lớn là 5 phần thì số bé là 3 phần. Hiệu số phần bằng nhau là:
$5-3=2$ (phần)

Số lớn là: $36:2\times 5=90$

Số bé là: $36:2\times 3=54$

a: =7/8:(2/9-18+1/36)-5/12

=-7/142-5/12=-397/852

b: =3/7(4/9+5/9:6/12)=2/3

c: =5^8(16/31-47/31)+1/3=-5^8+1/3

d: =7/2(3/8+5/8:4/15)=609/64

dễ mk bn cho mình hỏi nhé câu 4 là \(\frac{1}{2\cdot3}\)hay là\(\frac{1}{2}\cdot3\)

Cau 1

A=17/72     B=16      C=-5/21

Cau 2

a)    x=1      b)    -10/3

Câu 8:

  x=1/5

Câu 9

a: 2

b:41/36

thực hành ra luôn mọi người

Câu 8 

3/5 : x = 3 

        x = 3/5 : 3 

        x = 1/5

Câu 9 

a) 1/5 + 4/11 + 4/5 + 7/11

= ( 1/5 + 4/5 ) + ( 4/11 + 7/11 )

= 1                  +           1 

= 2 

b) 5/6 + ( 5/9 - 1/4 ) 

  = 5/6 +    7/18

= 11/9

\(\frac{1}{3}:x-\frac{2}{3}=\frac{5}{6}+\frac{7}{8}\)

\(\frac{1}{3}:x-\frac{2}{3}=\frac{41}{24}\)

\(\frac{1}{3}:x=\frac{19}{8}\)

\(x=\frac{8}{57}\)

\(\frac{2}{5}-x:\frac{3}{5}=\frac{6}{7}\)

\(x:\frac{3}{5}=\frac{-16}{35}\)

\(x=\frac{-48}{175}\)

\(\frac{4}{5}-\frac{26}{m}=\frac{-8}{15}\)

\(\frac{26}{m}=\frac{4}{3}\)

=> 26 x 3 = m x 4

   78 = m x 4

         m = 19,5

Câu 1 :\(\frac{1}{3}\div x-\frac{2}{3}=\frac{5}{6}+\frac{7}{8}\)

\(\Leftrightarrow\frac{1}{3x}=\frac{5}{6}+\frac{7}{8}+\frac{2}{3}\)

\(\Leftrightarrow\frac{1}{3x}=\frac{4\cdot5}{24}+\frac{7\cdot3}{24}+\frac{2\cdot8}{24}\)

\(\Leftrightarrow\frac{1}{3x}=\frac{20}{24}+\frac{21}{24}+\frac{16}{24}\)

\(\Leftrightarrow\frac{1}{3x}=\frac{57}{24}\)

\(\Leftrightarrow24=57\cdot3x\)

\(\Leftrightarrow24=171x\)

\(\Leftrightarrow x=\frac{24}{171}=\frac{8}{57}\)

Câu 2: \(\frac{2}{5}-x\div\frac{3}{5}=\frac{6}{7}\)

\(\Leftrightarrow\frac{-5x}{3}=\frac{6}{7}-\frac{2}{5}\)

\(\Leftrightarrow\frac{-5x}{3}=\frac{5\cdot6}{35}-\frac{2\cdot7}{35}\)

\(\Leftrightarrow\frac{-5x}{3}=\frac{30}{35}-\frac{14}{35}\)

\(\Leftrightarrow-\frac{5x}{3}=\frac{16}{35}\)

\(\Leftrightarrow-175x=48\)

\(\Leftrightarrow x=-\frac{48}{175}\)

Câu 3: \(\frac{4}{5}-\frac{26}{m}=-\frac{8}{15}\)

\(\Leftrightarrow\frac{26}{m}=\frac{4}{5}-\left(-\frac{8}{15}\right)\)

\(\Leftrightarrow\frac{26}{m}=\frac{4}{5}+\frac{8}{15}\)

\(\Leftrightarrow\frac{26}{m}=\frac{12}{15}+\frac{8}{15}\)

\(\Leftrightarrow\frac{26}{m}=\frac{20}{15}\)

\(\Leftrightarrow20m=26\cdot15=390\)

\(\Leftrightarrow m=\frac{390}{20}=\frac{39}{2}\)

1. a

\(\dfrac{8}{5}-\dfrac{5}{6}\cdot\dfrac{3}{4}\)

\(=\dfrac{8}{5}-\dfrac{5\cdot3}{3\cdot2\cdot4}\)

\(=\dfrac{8}{5}-\dfrac{5}{8}=\dfrac{39}{40}\)

1.b

\(=\dfrac{7}{8}+\dfrac{5}{6}\cdot\dfrac{3}{2}\)

\(=\dfrac{7}{8}+\dfrac{5\cdot3}{3\cdot2\cdot2}\)

\(=\dfrac{7}{8}+\dfrac{5}{4}=\dfrac{17}{8}\)

2.a

\(\dfrac{4}{5}+x=\dfrac{11}{10}\)

\(x=\dfrac{11}{10}-\dfrac{4}{5}=\dfrac{3}{10}\)

2.b

\(x-\dfrac{3}{4}=\dfrac{5}{7}\)

\(x=\dfrac{5}{7}+\dfrac{3}{4}=\dfrac{41}{28}\)

Câu 1 :

a, 8.( -5 ).( -4 ).2

= [ 8.2 ].[( -5 ).(-4 ]

= 16.20

= 320

b, \(1\frac{3}{7}+\frac{-1}{3}+2\frac{4}{7}\)

\(=\frac{10}{7}+\frac{-1}{3}+\frac{18}{7}\)

\(=\frac{11}{3}\)

c, \(\frac{8}{5}.\frac{2}{3}+\frac{-5.5}{3.5}\)

\(=\frac{8}{3}+\frac{-5}{3}\)

\(=\frac{3}{3}=1\)

d, \(\frac{6}{7}+\frac{5}{8}:5-\frac{3}{16}.\left(-2\right)^2\)

\(=\frac{6}{7}+\frac{1}{8}-\frac{3}{16}.4\)

\(=\frac{55}{56}-\frac{3}{4}\)

\(=\frac{13}{56}\)

Câu 2 :

a, 2x + 10 = 16

    2x = 16 + 10

    2x = 26

    x = 26 : 2

    x = 13

b, \(x-\frac{1}{3}=\frac{5}{4}\)

\(x=\frac{5}{4}+\frac{1}{3}\)

\(x=\frac{19}{12}\)

c, \(2x+3\frac{1}{3}=7\frac{1}{3}\)

\(2x+\frac{10}{3}=\frac{22}{3}\)

\(2x=\frac{22}{3}-\frac{10}{3}\)

\(2x=4\)

\(x=4:2\)

\(x=2\)

d, \(\left(\frac{2}{11}+\frac{1}{3}\right)x=\left(\frac{1}{7}-\frac{1}{8}\right).56\)

\(\frac{17}{33}x=1\)

\(x=1-\frac{17}{33}\)

\(x=\frac{16}{33}\)