a) 3/5 + 2/5 = 5/5 = 1

b) 4/6 =2/3 ; 18/27 = 2/3

    2/3 + 2/3 = 4/3

c) mình ko biết làm

a) \(\frac{3}{5}+\frac{2}{5}=\frac{3+2}{5}=\frac{5}{5}=1\)

b)\(\frac{4}{6}=\frac{2}{3}\)

\(\frac{18}{27}=\frac{2}{3}\)

\(\frac{2}{3}+\frac{2}{3}=\frac{2+2}{3}=\frac{4}{3}\)

c)\(\frac{15}{25}=\frac{3}{5}\)

\(\frac{6}{21}=\frac{2}{7}\)

\(\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{21+10}{35}=\frac{31}{35}\)

a: =1/4+1/4=2/4=1/2

b: =3/5+3/5=6/5

c: =5/9+7/9=12/9=4/3

a, 1/4+1/4=2/4=1/4

b, 3/5+3/5=6/5

c, 5/9+7/9=12/9=4/3

a)1/4+1/4=2/4=1/4

b) 3/5+3/5=6/5

c) 5/9+7/9=12/9=4/3

a)8/5-18/27=216/135-90/135=126/135

b)3/5-1/3=9/15-5/15=4/15(rút gọn p/s)

c)1/3-1/5=5/15-3/15=2/15

d)6/7-12/27=162/189-84/189=78/189

a) 8/5 - 18/27

= 8/5 - 2/3

= 24/15 - 10/15

= 14/15

b) 12/20 - 6/18

= 3/5 - 1/3

= 9/15 - 5/15

= 4/15

c) 8/24 - 5/25

= 1/3 - 1/5

= 5/15 - 3/15

= 2/15

d) 18/21 - 12/27

= 6/7 - 4/9

= 54/63 - 28/63

= 26/63

a: =2/3-1/3=1/3

b: =3/5-1/7=21/35-5/35=16/35

c: =2/3-1/2=4/6-3/6=1/6

tự làm , ngu

5/7>6/21

18/24>15/25

12/13=1212/1313

\(\dfrac{5}{7}\)>\(\dfrac{6}{21}\)

\(\dfrac{18}{24}\)>\(\dfrac{15}{25}\)

\(\dfrac{12}{13}\)=\(\dfrac{1212}{1313}\)

\(\frac{15}{25}+\frac{6}{21}=\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)

             HT 

TL

= \(\frac{31}{35}\)

nhaaaaa

nhớ tíc cho mk

\(\frac{15}{25}+\frac{6}{21}=\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}·\)

HT

15/25 + 6/21 = 31/35

15/25 + 6/21 = 31/35

15/25=15:5=3,25:5=5

6/21=6:3=2,21:3=7

3/5+2/7=21/35+10/35=21+10/35=31/35

a, 15/25 - 3/21 = 3/5 - 1/7 = 21/35 - 5/35 = 18/35

b, 24/36 - 6/12 = 2/3 - 1/2 = 4/6 - 3/6 = 1/6

a)15/25-3/21=3/5-1/7=16/35                b)24/36-6/12=2/3-1/2=1/6

Cảm ơn

\(\frac{3}{5}-\frac{5}{35}=\frac{21}{35}-\frac{5}{35}=\frac{16}{35}\)

\(\frac{18}{27}-\frac{2}{6}=\frac{1}{3}\)

\(\frac{15}{25}-\frac{3}{21}=\frac{16}{35}\)

\(\frac{24}{36}-\frac{6}{12}=\frac{1}{6}\)

tích đúng cho mk nhé