a: =8/5-2/3=24/15-10/15=14/15

12/20-6/18=3/5-1/3=9/15-5/15=4/15

b: 18/21-12/27=6/7-7/9=54/63-49/63=5/63

8/12-20/50=2/3-2/5=10/15-6/15=4/15

\(a,\dfrac{8}{5}-\dfrac{18}{27}=\dfrac{8}{5}-\dfrac{2}{3}=\dfrac{14}{15}\\ \dfrac{12}{20}-\dfrac{6}{18}=\dfrac{3}{5}-\dfrac{1}{3}=\dfrac{4}{15}\\ b,\dfrac{18}{21}-\dfrac{12}{27}=\dfrac{6}{7}-\dfrac{4}{9}=\dfrac{26}{63}\\ \dfrac{8}{12}-\dfrac{20}{50}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{4}{15}\)

Không rút gọn được nữa đâu em nhé

Ko rút gọn được

Tối giản rồi bn

6/18=1/3

6/24=1/4

1/3-1/4=4/12-3/12=1/12

18/27=2/3

5/15=1/3

2/3-1/3=1/3

có nha

rút gọn cho 2 bạn nhé

có nha 

14/18 chia hết cho 2

b: 12/20+6/18=3/5+1/3=9/15+5/15=14/15

c: 8/12+20/30=2/3+2/3=4/3

d: 10/12+12/36=5/6+2/6=7/6

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

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

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

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

tích đúng cho mk nhé

\(\dfrac{6}{36}+\dfrac{5}{6}=\dfrac{1}{6}+\dfrac{5}{6}=\dfrac{6}{6}=1\\ \dfrac{1}{4}+\dfrac{5}{30}=\dfrac{1}{4}+\dfrac{1}{6}=\dfrac{6}{24}+\dfrac{4}{24}=\dfrac{10}{24}=\dfrac{5}{12}\\ \dfrac{5}{56}+\dfrac{3}{21}=\dfrac{5}{56}+\dfrac{1}{7}=\dfrac{5}{56}+\dfrac{8}{56}=\dfrac{13}{56}\\\dfrac{12}{18}+\dfrac{12}{42}=\dfrac{2}{3}+\dfrac{2}{7}=\dfrac{14}{21}+\dfrac{6}{21}=\dfrac{20}{21} \)

6/36 + 5/6=1/6+5/6=6/6=1

1/4 + 5/30=1/4+1/6=6/24+4/24=10/24=5/12

5/56 + 3/21=5/56=1/7=5/56+8/56=13/56

12/18 + 12/42=2/3+2/7=14/21+6/21=20/21

\(a,\dfrac{6}{36}+\dfrac{5}{6}=\dfrac{1}{6}+\dfrac{5}{6}=\dfrac{6}{6}=1\\ b,\dfrac{1}{4}+\dfrac{5}{30}=\dfrac{1}{4}+\dfrac{1}{6}=\dfrac{6}{24}+\dfrac{4}{24}=\dfrac{5}{12}\\ c,\dfrac{5}{56}+\dfrac{3}{21}=\dfrac{5}{56}+\dfrac{8}{56}=\dfrac{13}{56}\\ d,\dfrac{12}{18}+\dfrac{12}{42}=\dfrac{14}{21}+\dfrac{6}{21}=\dfrac{20}{21}\)

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

-3/6, 2/3 (18/27), 1 (12/12), 7/4, 2 (8/4), 11/5