Luyện tập chung

`a)`

`2/9 - 7/8 xx x = 1/3 `

`=>  7/8 xx x = 2/9 - 1/3`

`=>  7/8 xx x =2/9 - 3/9`

`=>  7/8 xx x =-1/9`

`=>x=-1/9 : 7/8`

`=>x=-1/9 xx 8/7`

`=>x=-8/63`

`b)`

`(14 ,17 - x ) xx 2/9 = 1/3 `

`=> 14 ,17 - x = 1/3 : 2/9`

`=>  14 ,17 - x =1/3 xx 9/2`

`=>  14 ,17 - x =3/2`

`=>x= 14,17 - 3/2`

`=>x=12,67`

`c)`

`x xx 3 1/3 = 3 1/3 : 4 1/4 `

`=>x xx10/3 = 10/3 : 17/4`

`=>x xx10/3 = 10/3 xx 4/17`

`=>x xx10/3 = 40/51`

`=>x=40/51 : 10/3`

`=>x=40/51 xx 3/10`

`=>x=4/17`

\(a,-\dfrac{7}{8}x=\dfrac{2}{9}-\dfrac{1}{3}\\ -\dfrac{7}{8}x=\dfrac{2-3}{9}\\ -\dfrac{7}{8}x=-\dfrac{1}{9}\\ x=-\dfrac{1}{9}:\left(-\dfrac{7}{8}\right)\\ x=\dfrac{8}{63}\\ b,\left(14,17-x\right)=\dfrac{1}{3}:\dfrac{2}{9}\\ \left(14,17-x\right)=\dfrac{3}{2}\\ x=14,17-\dfrac{3}{2}\\ x=\dfrac{1267}{100}\\ c,x.\dfrac{10}{3}=\dfrac{10}{3}:\dfrac{17}{4}\\ x.\dfrac{10}{3}=\dfrac{40}{51}\\ x=\dfrac{40}{51}:\dfrac{10}{3}\\ x=\dfrac{4}{17}\)

\(a,x:\dfrac{8}{3}=7\\ x=7.\dfrac{8}{3}\\ x=\dfrac{56}{3}\\ b,\dfrac{17}{3}:x=\dfrac{11}{3}-\dfrac{5}{2}\\ \dfrac{17}{3}:x=\dfrac{22-15}{6}\\ \dfrac{17}{3}:x=\dfrac{7}{6}\\ x=\dfrac{17}{3}:\dfrac{7}{6}\\ x=\dfrac{34}{7}\)

a: =>x:8/3=7

hay x=56/3

b: =>17/3:x=3+2/3-2-1/2=1+1/6=7/6

=>x=17/3:7/6=17/3x6/7=102/21=34/7

`x : 2 2/3 = 4 3/1`

`x  : 8/3 = 7`

`x=7 xx 8/3`

`x=56/3`

Vậy `x=56/3`

____________________________________

`5 2/3 : x = 3 2/3 - 2 1/2`

`17/3 : x = 11/3 - 5/2`

`17/3 : x = 22/6 - 15/6`

`17/3 : x = 7/6`

`x=17/3 : 7/6`

`x=17/3 xx 6/7`

`x=34/7`

Vậy `x=34/7`

`x xx 3 1/2 = 4 3/4`

`x xx7/2 = 19/4`

`x=19/4 : 7/2`

`x=19/4 xx 2/7`

`x=19/14`

Vậy `x=19/14`

____________________________

`x : 2 2/3 =4 1/4`

`x: 8/3 = 17/4`

`x=17/4 xx 8/3`

`x=34/3`

Vậy `x=34/3`

a: \(\Leftrightarrow x\cdot\dfrac{7}{2}=\dfrac{19}{4}\)

\(\Leftrightarrow x=\dfrac{19}{4}:\dfrac{7}{2}=\dfrac{19}{4}\cdot\dfrac{2}{7}=\dfrac{19}{14}\)

b: \(\Leftrightarrow x:\dfrac{8}{3}=\dfrac{17}{4}\)

\(\Leftrightarrow x=\dfrac{17}{4}\cdot\dfrac{8}{3}=\dfrac{34}{3}\)

`a) 2 1/3 + 3 5/6 - 1 1/12=7/3 +23/6 - 13/12=28/12 + 46/12-13/12=(28+46-13)/12=61/12`

`b) 6/7 : ( 1/2 xx 3/4 ) - 5/8 = 6/7 : 3/8 - 5/8= 6/7 xx 8/3 - 5/8= 16/7-5/8=93/56`

`c) 34-2 :( 3/5 - 1/2 )=34-2 :1/10=34- 2 xx 10/1= 34- 20=14`

`đ) 4 1/2 + 1/2 : 5 1/2 =9/2 + 1/2 : 11/2= 9/2 + 1/2 xx 2/11=9/2 + 1/11=101/22`

\(=\dfrac{5932+\left(5932+69\right)\left(5932-1\right)}{5932\left(5932+69\right)-64}\)

\(=\dfrac{5932+5932^2+68\cdot5932-69}{5932^2+69\cdot5932-64}\)

\(=1-\dfrac{5}{5932^2+69\cdot5932-64}\)

\(\left(\dfrac{5}{2}+\dfrac{1}{3}\right):\left(1-\dfrac{2}{3}\right)=\left(\dfrac{15}{6}+\dfrac{2}{6}\right):\dfrac{1}{3}=\dfrac{17}{6}.3=\dfrac{17}{2}\)

\(\left(\dfrac{5}{2}-\dfrac{1}{3}\right)\times\dfrac{9}{2}-\dfrac{6}{7}=\left(\dfrac{15}{6}-\dfrac{2}{6}\right)\times\dfrac{9}{2}-\dfrac{6}{7}=\dfrac{13}{6}\times\dfrac{9}{2}-\dfrac{6}{7}=\dfrac{39}{4}-\dfrac{6}{7}=\dfrac{249}{28}\)\(\dfrac{6}{7}:\left(\dfrac{1}{2}\times\dfrac{3}{4}\right)-\dfrac{5}{8}=\dfrac{6}{7}:\dfrac{3}{8}-\dfrac{5}{8}=\dfrac{16}{7}-\dfrac{5}{8}=\dfrac{93}{56}\)

`( 5/2 + 1/3 ) : (1- 2/3 )`

` =(15/6 + 2/6):(3/3 - 2/3)`

`=17/6 : 1/3`

`=17/6 xx3`

`=17/2`

`( 5/2 - 1/3 ) xx 9/2 - 6/7 `

`=(15/6 - 2/6)xx 9/2 - 6/7`

`=17/6 xx 9/2 -6/7`

`=51/4 - 6/7`

`=333/28`

`6/7 : ( 1/2 xx 3/4 ) - 5/8 `

`=6/7 : 3/8 - 5/8`

`=6/7 xx 8/3 - 5/8`

`=16/7 - 5/8`

`=93/56`

`[ 5/2 + 1/3 ] : [ 1- 2/3 ] =17/6 : 1/3= 17/6 xx 3/1= 17/2`

`[ 5/2 - 1/3 ] xx 9/2 - 6/7 =13/6 xx 9/2 - 6/7= 39/4 - 6/7=249/28`

`6/7 : [ 1/2 xx 3/4 ] - 5/8 =6/7 : 3/8 - 5/8=6/7 xx 8/3 - 5/8=16/7 - 5/8=93/56`

`2/11:1/3xx3/2=6/11xx3/2=9/11`

`1/2:1/4-1/6=1/2xx4-1/6=2-1/6=11/6`

`2/3-1/4+2/9=24/36-9/36+8/36=23/36`

`5/2+1/3xx3/2=5/2+1/2=6/2=3`

`=3/11 :1/3=9/11`

`=2- 1/6=11/6`

`=5/12 +2/9=23/36`

`=5/2 +1/2=6/2=3`

\(\dfrac{6}{7}+\dfrac{7}{8}=\dfrac{48}{56}+\dfrac{49}{56}=\dfrac{97}{56}\)

\(\dfrac{4}{7}-\dfrac{11}{42}=\dfrac{24}{42}-\dfrac{11}{42}=\dfrac{13}{42}\)

\(\dfrac{5}{3}\times\dfrac{2}{7}:\dfrac{4}{9}=\dfrac{5}{3}\times\dfrac{2}{7}\times\dfrac{9}{4}=\dfrac{15}{14}\)

\(\dfrac{2}{11}:\dfrac{1}{3}\times\dfrac{2}{5}=\dfrac{2}{11}\times3\times\dfrac{2}{5}=\dfrac{12}{55}\)

\(\dfrac{6}{7}+\dfrac{7}{8}=\dfrac{48}{56}+\dfrac{49}{56}=\dfrac{97}{56}\)
 

\(\dfrac{4}{7}-\dfrac{11}{42}=\dfrac{24}{42}-\dfrac{11}{42}=\dfrac{13}{42}\)
 

\(\dfrac{5}{3}\times\dfrac{2}{7}:\dfrac{4}{9}=\dfrac{10}{21}\cdot\dfrac{9}{4}=\dfrac{15}{14}\)
 

\(\dfrac{2}{11}:\dfrac{1}{3}\times\dfrac{2}{5}=\dfrac{2}{11}\times3\times\dfrac{2}{5}=\dfrac{6}{11}\cdot\dfrac{2}{5}=\dfrac{12}{55}\)

số ?

22 + 41 > 61 + 1

44 < 40 + 5 < 16 + 30 

22 + 41 + 61 + 1

44 < 40 + 5 < 16 + 30

22 + 41 > 61 + .1 hoặc 0 hoặc 2

44 < 40 + 5.. < 16 + 30 

45 phút 17 giây - 23 phút 27 giây = 21 phút 50 giây

13 giờ 25 phút : 5 = 2 giờ 41 phút

a: =2717 giây-1407 giây

=1310 giây

b: =805 phút:5=161 phút

21 phút 50 giây

2 giờ 41 phút