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7 tháng 8 2023

A. 2/3 + 3/5 = 19/15

B. 4 và 1/4 - 0,25 = 4 

C. 12 . 2 và 1/3 = 28

D. 8 và 2/7 + 4 và 3/5 + 1 và 5/7 + 5 và 2/5

=   58/7 + 23/5 + 12/7 + 27/5

=   ( 27/5 + 12/5 ) + ( 58/7 + 12/7 )

=   39/5 + 10

=   89/5

=  39/5 + 70/7

Giải:

a) \(11\dfrac{3}{4}.\left(6\dfrac{5}{6}-4\dfrac{1}{2}+1\dfrac{2}{3}\right)\) 

\(=\dfrac{47}{4}.\left(\dfrac{41}{6}-\dfrac{9}{2}+\dfrac{5}{3}\right)\) 

\(=\dfrac{47}{4}.4\) 

\(=47\) 

b) \(\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\) 

\(=\left(\dfrac{47}{8}-\dfrac{9}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}\) 

\(=\dfrac{25}{8}:\dfrac{75}{26}\) 

\(=\dfrac{13}{12}\)

c) \(\left(17\dfrac{13}{15}-3\dfrac{3}{7}\right)-\left(2\dfrac{12}{15}-4\right)\) 

\(=\dfrac{268}{15}-\dfrac{24}{7}-\dfrac{14}{5}+4\) 

\(=\left(\dfrac{268}{15}-\dfrac{14}{5}\right)+\left(\dfrac{-24}{7}+4\right)\) 

\(=\dfrac{226}{15}+\dfrac{4}{7}\) 

\(=\dfrac{1642}{105}\) 

d) \(2\dfrac{2}{3}.\left(\dfrac{-4}{5}.0,375.-10.\dfrac{-15}{24}\right)\) 

\(=\dfrac{8}{3}.\left(\dfrac{-4}{5}.\dfrac{3}{8}.-10.\dfrac{-5}{8}\right)\) 

\(=\left(\dfrac{8}{3}.\dfrac{3}{8}\right).\left(\dfrac{-4}{5}.\dfrac{-5}{8}.-10\right)\) 

\(=1.-5\) 

\(=-5\) 

Chúc bạn học tốt!

Bài 1: 

a: -8/12<0<-3/-4

b: -56/24<0<7/3

c: 4/25<1<15/13

=>-4/25>-15/13

Bài 2: 

a: =-60/45=-4/3

b: =4/15-3/2-8/5=8/30-45/30-48/30=-85/30=-17/6

11 tháng 12 2022

b

 

 
a  
c  

 

13 tháng 6 2023

a) 5 : 3/4 - 4 4/5 : 3/4

= 5 . 4/3 - 24/5 . 4/3

= (5 - 24/5) . 4/3

= 1/5 × 4/3

= 4/15

b) -3/5 . 2/7 + (-3/7) . 3/5 + (-3/7)

= (-3/7) . (2/5 + 3/5 + 1)

= (-3/7) . 2

= -6/7

c) [(-4 2/7) . 7/11 + 7/11 . (5 1/3)] . 5 - 5 2/3

= (-30/7 . 7/11 + 7/11 . 16/3) . 5 - 17/3

= (-30/11 + 112/33) . 5 - 17/3

= 2/3 . 5 - 17/3

= 10/3 - 17/3

= -7/3

d) 5/39 . [(7 4/5) . (1 2/3) + (8 1/3) . (7 4/5)]

= 5/39 . (39/5 . 5/3 + 25/3 . 39/5)

= 5/39 . 39/5 . (5/3 + 25/3)

= 1 . 10

= 10

8 tháng 6 2020

Bài làm

a) \(\left(\frac{3}{8}+\frac{-1}{4}+\frac{5}{12}\right):\frac{2}{3}\)

\(=\left(\frac{9}{24}+\frac{-6}{24}+\frac{10}{24}\right).\frac{3}{2}\)

\(=\frac{13}{24}.\frac{3}{2}\)

\(=\frac{39}{48}\)

b) \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{11}+1\frac{5}{7}\)

\(=-\frac{5}{7}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{12}{7}\)

\(=-\frac{5}{7}.1+\frac{12}{7}\)

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

\(=1\)

c) \(0,25:\left(10,3-9,8\right)-\frac{3}{4}\)

\(=\frac{25}{100}:\left(0,5\right)-\frac{3}{4}\)

\(=\frac{5}{4}:\frac{1}{2}-\frac{3}{4}\)

\(=\frac{5}{4}.2-\frac{3}{4}\)

\(=\frac{5}{2}-\frac{3}{4}\)

\(=\frac{10}{4}-\frac{3}{4}=\frac{7}{4}\)

d) \(-\frac{5}{9}.\frac{13}{28}-\frac{13}{28}.\frac{4}{9}\)

\(=-\frac{13}{28}\left(\frac{5}{9}+\frac{4}{9}\right)\)

\(=-\frac{13}{28}.\frac{9}{9}\)

\(=-\frac{13}{28}.1\)

\(=-\frac{13}{28}\)

a: \(\dfrac{3}{5}-\dfrac{7}{4}=\dfrac{12}{20}-\dfrac{35}{20}=\dfrac{-23}{20}\)

b: \(\dfrac{4}{5}:\dfrac{-8}{15}=\dfrac{-4}{5}\cdot\dfrac{15}{8}=\dfrac{-60}{40}=\dfrac{-3}{2}\)

c: \(=7+\dfrac{5}{9}-2-\dfrac{3}{4}-3-\dfrac{5}{9}=2-\dfrac{3}{4}=\dfrac{5}{4}\)

d: \(=\dfrac{-3}{7}\left(\dfrac{4}{19}+\dfrac{15}{19}\right)+\dfrac{5}{7}=\dfrac{2}{7}\)

Giải:

a) \(\left(9\dfrac{4}{9}+5\dfrac{2}{3}\right)-5\dfrac{1}{2}\) 

\(=\left(\dfrac{85}{9}+\dfrac{17}{3}\right)-\dfrac{11}{2}\) 

\(=\dfrac{136}{9}-\dfrac{11}{2}\) 

\(=\dfrac{173}{18}\) 

b) \(\dfrac{13}{9}.\dfrac{15}{4}-\dfrac{13}{9}.\dfrac{7}{4}-\dfrac{13}{9}.\dfrac{5}{4}\) 

\(=\dfrac{13}{9}.\left(\dfrac{15}{4}-\dfrac{7}{4}-\dfrac{5}{4}\right)\) 

\(=\dfrac{13}{9}.\dfrac{3}{4}\) 

\(=\dfrac{13}{12}\) 

c) \(\dfrac{2}{3}+\dfrac{5}{8}-\dfrac{-1}{3}+0,375\) 

\(=\left(\dfrac{2}{3}-\dfrac{-1}{3}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)\) 

\(=1+1\) 

\(=2\)

d) \(75\%-3\dfrac{1}{2}+1,5:\dfrac{10}{7}\) 

\(=\dfrac{3}{4}+\dfrac{7}{2}+\dfrac{3}{2}:\dfrac{10}{7}\) 

\(=\dfrac{3}{4}+\dfrac{7}{2}+\dfrac{21}{20}\) 

\(=\dfrac{53}{10}\) 

e) \(1\dfrac{13}{15}.\left(0,5\right)^2.3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\) 

\(=\dfrac{28}{15}.\dfrac{1}{4}.3+\left(\dfrac{8}{15}-\dfrac{79}{60}\right):\dfrac{47}{24}\) 

\(=\dfrac{7}{5}+\dfrac{-47}{60}:\dfrac{47}{24}\) 

\(=\dfrac{7}{5}+\dfrac{-2}{5}\) 

\(=1\)