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30 tháng 3 2022

a) \(\dfrac{4}{7}+\dfrac{2}{8}=\dfrac{32}{56}+\dfrac{14}{56}=\dfrac{46}{56}=\dfrac{23}{28}\)

b) \(\dfrac{8}{6}-\dfrac{8}{24}=\dfrac{32}{24}-\dfrac{8}{24}=\dfrac{24}{24}=1\)

c) \(\dfrac{9}{28}\times\dfrac{14}{9}=\dfrac{126}{252}=\dfrac{1}{2}\)

d) \(\dfrac{7}{6}\div\dfrac{2}{3}=\dfrac{7}{6}\times\dfrac{3}{2}=\dfrac{21}{12}\)

30 tháng 3 2022

1. \(\dfrac{4}{7}+\dfrac{2}{8}=\dfrac{32}{56}+\dfrac{14}{56}=\dfrac{32+14}{56}=\dfrac{46}{56}=\dfrac{23}{28}\)

2. \(\dfrac{8}{6}-\dfrac{8}{24}=\dfrac{32}{24}-\dfrac{8}{24}=\dfrac{32-8}{24}=\dfrac{24}{24}=1\)

3. \(\dfrac{9}{28}\text{×}\dfrac{14}{9}=\dfrac{9\text{×}14}{28\text{×}9}=\dfrac{126}{252}=\dfrac{7}{14}\)

4. \(\dfrac{7}{6}:\dfrac{2}{3}=\dfrac{7}{6}\text{×}\dfrac{3}{2}=\dfrac{7\text{×}3}{6\text{×}2}=\dfrac{21}{12}=\dfrac{7}{4}\)

2 tháng 7 2018

A) 137/ 12

B) 4

C) 5

2 tháng 7 2018

b, 3/5 + 4/7 + 2/8 + 10/25 + 9/21 + 28/16

= 3/5 + 4/7 + 2/8 + 2/5 + 3/7 + 14/8

= (3/5 + 2/5) + ( 4/7 + 3/7) + ( 2/8 + 14/8)

= 1 + 1 + 7/4

= 2 + 7/4 = 15/4

c , 8/7 + 7/6 + 5/8 + 10/12 + 24/28 + 6/16 

= c , 8/7 + 7/6 + 5/8 + 5/6 + 6/7 + 1/2

= (8/7 + 6/7) + (7/6 + 5/6) + 5/8 + 1/2

= 14/7 + 12/6 + 5/8 + 1/2

= 2 + 2 + 5/8 + 1/2

= 4 + 9/8 = 41/8

24 tháng 4 2023

\((\)125-120\()\)x45

5x45=225

\(\dfrac{30x25x7x8}{75x8x12x14}\)=\(\dfrac{10\cdot1\cdot7\cdot1}{1\cdot1\cdot1\cdot12\cdot2}\)=\(\dfrac{70}{24}\)

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`

a: \(=\dfrac{5}{14}\left(\dfrac{2}{9}+\dfrac{7}{9}+1\right)=\dfrac{5}{14}\cdot2=\dfrac{5}{7}\)

b: \(=\dfrac{6}{8}\left(\dfrac{6}{7}-6\right)=\dfrac{6}{8}\cdot\dfrac{-36}{7}=\dfrac{-216}{56}=\dfrac{-27}{7}\)

11 tháng 4 2023

ko có âm à nha

29 tháng 4 2022

                                                                                                                                                                                                                                                                                                                                                                                               

25 tháng 2 2019

\(a)9+\frac{24}{25}=\frac{9\cdot25+24}{25}=\frac{249}{25}\)

\(b)\frac{1}{20}+\frac{1}{4}+\frac{2}{5}=\frac{1}{20}+\frac{5}{20}+\frac{8}{20}=\frac{1+5+8}{20}=\frac{14}{20}=\frac{7}{10}\)

\(c)\frac{7}{12}+4=\frac{7}{12}+\frac{4}{1}=\frac{7+48}{12}=\frac{55}{12}\)

\(d)10+\frac{9}{8}=\frac{10}{1}+\frac{9}{8}=\frac{80+9}{8}=\frac{89}{8}\)

\(e)\frac{1}{4}+\frac{2}{25}+\frac{9}{100}=\frac{25}{100}+\frac{8}{100}+\frac{9}{100}=\frac{25+8+9}{100}=\frac{42}{100}=\frac{21}{50}\)

Còn 3 câu làm tương tự

25 tháng 2 2019

Ba câu còn lại mình làm luôn :D

\(f)\frac{28}{90}+6=\frac{14}{45}+6=\frac{14}{45}+\frac{6}{1}=\frac{14+270}{45}=\frac{284}{45}\)

\(g)\frac{3}{7}+\frac{4}{9}+\frac{4}{7}+\frac{7}{11}=(\frac{3}{7}+\frac{4}{7})+\frac{4}{9}+\frac{4}{11}=1+\frac{4}{9}+\frac{4}{11}\)

\(=\frac{7}{7}+\frac{4}{9}+\frac{4}{11}=\frac{693+308+252}{693}=\frac{1253}{693}=\frac{179}{99}\)

\(h)\frac{1}{8}+\frac{1}{12}+\frac{3}{8}+\frac{5}{12}=(\frac{1}{8}+\frac{3}{8})+(\frac{1}{12}+\frac{5}{12})=\frac{4}{8}+\frac{6}{12}=\frac{1}{2}+\frac{1}{2}=1\)

16 tháng 4 2022

Giải chi tiết cho mình nha

2/5 + 11/15 = 17/15
7/8 - 7/9 = 7/72
11/13 x 26/31 = 22/31
16/24 : 4 = 1/6
30 : 6/5 = 25
9/16 : 4 = 9/64
1/2 : 1/3 x 8/15 = 3/2 x 8/15 = 4/5