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P
Phong
CTVHS
9 tháng 7 2023

\(\dfrac{9}{15}+\dfrac{3}{5}\)

\(=\dfrac{9:3}{15:3}+\dfrac{3}{5}\)

\(=\dfrac{3}{5}+\dfrac{3}{5}\)

\(=\dfrac{3+3}{5}\)

\(=\dfrac{6}{5}\)

9 tháng 7 2023

   \(\dfrac{9}{15}\) \(+\) \(\dfrac{3}{5}\)

=  \(\dfrac{3}{5}\) \(+\) \(\dfrac{3}{5}\)

=       \(\dfrac{6}{5}\)

17 tháng 8 2021

a) \(\dfrac{-5}{9}+\dfrac{3}{5}-\dfrac{3}{9}+\dfrac{-2}{5}\)

=\(\left(\dfrac{-5}{9}-\dfrac{3}{9}\right)+\left(\dfrac{3}{5}+\dfrac{-2}{5}\right)\)

=\(\dfrac{-8}{9}+\dfrac{1}{5}=-\dfrac{31}{45}\)

b) \(\dfrac{5}{17}-\dfrac{9}{15}-\dfrac{2}{17}+\dfrac{-2}{5}\)

=\(\left(\dfrac{5}{17}-\dfrac{2}{17}\right)-\left(\dfrac{9}{15}+\dfrac{2}{5}\right)\)

=\(\dfrac{3}{17}-1=\dfrac{-14}{17}\)

 

17 tháng 8 2021

a) (-5/9) + 3/5 - 3/9 + (-2/5)

= (-5/9) - 3/9 + 3/5 + (-2/5)

= (-2/9) + 1/5

= -1/45

b) 5/17 - 9/15 - 2/17 + (-2/5)

= 5/17 - 2/17 - 9/15 + (-2/5)

= 3/17 - 1/5

= -2/85

Chúc bạn học tốt!! ^^

 

28 tháng 10 2023

a: \(\dfrac{1}{8}+\dfrac{5}{8}=\dfrac{1+5}{8}=\dfrac{6}{8}=\dfrac{3}{4}\)

b: \(\dfrac{1}{15}+\dfrac{4}{15}=\dfrac{1+4}{15}=\dfrac{5}{15}=\dfrac{1}{3}\)

c: \(\dfrac{5}{9}+\dfrac{7}{9}=\dfrac{5+7}{9}=\dfrac{12}{9}=\dfrac{4}{3}\)

d: \(\dfrac{23}{100}+\dfrac{27}{100}=\dfrac{23+27}{100}=\dfrac{50}{100}=\dfrac{1}{2}\)

4 tháng 2 2024

a) 18+58=1+58=68=3418+58=1+58=68=34

b) 115+415=1+415=515=13115+415=1+415=515=13

c) 59+79=5+79=129=4359+79=5+79=129=43

d) 

12 tháng 9 2023

\(\dfrac{1}{3}-\dfrac{3}{5}+\dfrac{5}{7}-\dfrac{7}{9}+\dfrac{9}{11}-\dfrac{11}{13}+\dfrac{13}{15}+\dfrac{11}{13}-\dfrac{9}{11}+\dfrac{7}{9}-\dfrac{5}{7}+\dfrac{3}{5}-\dfrac{1}{3}\)
\(=\left(\dfrac{1}{3}-\dfrac{1}{3}\right)-\left(\dfrac{3}{5}-\dfrac{3}{5}\right)+\left(\dfrac{5}{7}-\dfrac{5}{7}\right)-\left(\dfrac{7}{9}-\dfrac{7}{9}\right)+\left(\dfrac{9}{11}-\dfrac{9}{11}\right)-\left(\dfrac{11}{13}-\dfrac{11}{13}\right)+\dfrac{13}{15}\)
\(=\dfrac{13}{15}\)

12 tháng 9 2023

3153+7597+1191311+1513+1311119+9775+5331
=(13−13)−(35−35)+(57−57)−(79−79)+(911−911)−(1113−1113)+1315=(3131)(5353)+(75

a: =-21/36-3/36=-24/36=-2/3

b: =43/12*1/2+5/24=43/24+5/24=2

c: =8/9+1/9=1

e: =1-1/4+1/4-1/7+...+1/97-1/100

=1-1/100=99/100

23 tháng 12 2023

a: \(1-\left(5\dfrac{4}{9}+a-7\dfrac{7}{18}\right):15\dfrac{3}{4}=0\)

=>\(\left(5+\dfrac{4}{9}+a-7-\dfrac{7}{18}\right):\dfrac{63}{4}=1\)

=>\(\left(a-2+\dfrac{1}{18}\right)=\dfrac{63}{4}\)

=>\(a-\dfrac{35}{18}=\dfrac{63}{4}\)

=>\(a=\dfrac{63}{4}+\dfrac{35}{18}=\dfrac{637}{36}\)

b: \(B=\left(\dfrac{2}{15}+\dfrac{5}{3}-\dfrac{3}{5}\right):\left(4\dfrac{2}{3}-2\dfrac{1}{2}\right)\)

\(=\dfrac{2+5\cdot5-3^2}{15}:\left(4+\dfrac{2}{3}-2-\dfrac{1}{2}\right)\)

\(=\dfrac{2+4^2}{15}:\left(2+\dfrac{2}{3}-\dfrac{1}{2}\right)\)

\(=\dfrac{18}{15}:\dfrac{13}{6}=\dfrac{6}{5}\cdot\dfrac{6}{13}=\dfrac{36}{65}\)

P
Phong
CTVHS
29 tháng 10 2023

\(\dfrac{1}{3}+\dfrac{2}{9}=\dfrac{3}{3\times3}+\dfrac{2}{9}=\dfrac{3}{9}+\dfrac{2}{9}=\dfrac{5}{9}\)

\(\dfrac{1}{2}+\dfrac{3}{8}=\dfrac{4}{2\times4}+\dfrac{3}{8}=\dfrac{4}{8}+\dfrac{3}{8}=\dfrac{7}{8}\)

\(\dfrac{5}{12}+\dfrac{2}{3}=\dfrac{5}{12}+\dfrac{2\times4}{3\times4}=\dfrac{5}{12}+\dfrac{8}{12}=\dfrac{13}{12}\)

\(\dfrac{5}{16}+\dfrac{3}{8}=\dfrac{5}{16}+\dfrac{3\times2}{8\times2}=\dfrac{5}{16}+\dfrac{6}{16}=\dfrac{11}{16}\)

\(\dfrac{4}{15}+\dfrac{3}{5}=\dfrac{4}{15}+\dfrac{3\times3}{5\times3}=\dfrac{4}{15}+\dfrac{9}{15}=\dfrac{13}{15}\)

\(\dfrac{8}{63}+\dfrac{7}{10}=\dfrac{8\times10}{63\times10}+\dfrac{7\times63}{10\times63}=\dfrac{80}{630}+\dfrac{441}{630}=\dfrac{521}{630}\)

21 tháng 2 2022

-2/15

-4/35

-5/3

10

-8/3

-7/2

-9

-4/3

Chúc em học giỏi

21 tháng 2 2022

\(=\dfrac{-2}{15}\\ =\dfrac{-4}{35}\\ =-1\\ =10\\ =\dfrac{-8}{3}\\ =-7\\ =-9\\ =\dfrac{-4}{3}\)

12 tháng 12 2021

\(a,\dfrac{3}{5}+\dfrac{1}{5}.\dfrac{-17}{9}=\dfrac{3}{5}-\dfrac{17}{45}=\dfrac{27}{45}-\dfrac{17}{45}=\dfrac{10}{45}=\dfrac{2}{9}\\ b,\left(-\dfrac{4}{15}-\dfrac{18}{19}\right)-\left(\dfrac{20}{19}+\dfrac{11}{15}\right)=-\dfrac{4}{15}-\dfrac{18}{19}-\dfrac{20}{19}-\dfrac{11}{15}=\left(-\dfrac{4}{15}-\dfrac{11}{15}\right)-\left(\dfrac{18}{19}+\dfrac{20}{19}\right)=-1-2=-3\)

12 tháng 12 2021

\(a,=\dfrac{3}{5}+\left(-\dfrac{17}{45}\right)=\dfrac{2}{9}\)

\(b,=-\dfrac{4}{15}-\dfrac{18}{19}-\dfrac{20}{19}-\dfrac{11}{15}=-3\)

10 tháng 12 2021

a.2/9
b.-3

10 tháng 12 2021

a.2/9 b.(-3)