Làm câu a)

2/3+4/3x3/6=2/3+2/3=4/3

Làm câu b)

9/24=3/8

Làm câu c)

355/985+355/985=710/985

Vậy.................

a.1

b.3/8

c.710/985

1313/1717 = ( 1313 :101)/(1717:101)=13/17

171717/191919=(171717:10101)/(191919:10101)=17/19

231231/343343=(231231:7007)/(343343:7007)=33/49

373737/494949=(373737:10101)/(494949:10101)=37/49

\(\frac{8}{5}-\frac{18}{27}\)

\(=\frac{8}{5}-\frac{2}{3}\)

\(=\frac{24}{15}-\frac{10}{15}\)

\(=\frac{14}{15}\)

\(\frac{12}{20}-\frac{6}{18}\)

\(=\frac{3}{5}-\frac{1}{3}\)

\(=\frac{9}{15}-\frac{5}{15}\)

\(=\frac{4}{15}\)

\(\frac{8}{24}-\frac{5}{25}\)

\(=\frac{1}{3}-\frac{1}{5}\)

\(=\frac{5}{15}-\frac{3}{15}\)

\(=\frac{2}{15}\)

\(\frac{18}{21}-\frac{12}{27}\)

\(=\frac{6}{7}-\frac{4}{9}\)

\(=\frac{54}{63}-\frac{28}{63}\)

\(=\frac{26}{63}\)

1)8/5-2/3=14/15

2)3/5-1/3=4/15

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

4)6/7-4/9=26/63

78/65=48/15

78/65 rút gọn = 16/5

câu 1: 0

\(\frac{24}{36}\)

1.

a) \(\frac{16}{24}-\frac{1}{3}=\frac{16}{24}-\frac{8}{24}=\)\(\frac{8}{24}=\frac{1}{3}\)

b) \(\frac{4}{5}-\frac{12}{60}=\frac{48}{60}-\frac{12}{60}=\frac{36}{60}=\frac{9}{15}\)

3.

a)\(\frac{17}{6}-\frac{2}{6}=\frac{17-2}{6}=\frac{15}{6}\)

b) \(\frac{16}{15}-\frac{11}{15}=\frac{16-11}{15}=\frac{5}{15}=\frac{1}{3}\)

c) \(\frac{19}{12}-\frac{13}{12}=\frac{19-13}{12}=\frac{6}{12}=\frac{1}{2}\)

a) 16 24 − 1 3 = 16 24 − 8 24 = 24 16 ​ − 3 1 ​ = 24 16 ​ − 24 8 ​ = 8 24 = 1 3 24 8 ​ = 3 1 ​ b) 4 5 − 12 60 = 48 60 − 12 60 = 36 60 = 9 15 5 4 ​ − 60 12 ​ = 60 48 ​ − 60 12 ​ = 60 36 ​ = 15 9 ​ 3. a) 17 6 − 2 6 = 17 − 2 6 = 15 6 6 17 ​ − 6 2 ​ = 6 17−2 ​ = 6 15 ​ b) 16 15 − 11 15 = 16 − 11 15 = 5 15 = 1 3 15 16 ​ − 15 11 ​ = 15 16−11 ​ = 15 5 ​ = 3 1 ​ c) 19 12 − 13 12 = 19 − 13 12 = 6 12 = 1 2 12 19 ​ − 12 13 ​ = 12 19−13 ​ = 12 6 ​ = 2 1 ​

\(\frac{90}{100}=\frac{90:10}{100:10}=\frac{9}{10}\)

\(\frac{64}{128}=\frac{64:64}{128:64}=\frac{1}{2}\)

\(\frac{17}{51}=\frac{17:17}{51:17}=\frac{1}{3}\)

\(\frac{152}{608}=\frac{152:152}{608:152}=\frac{1}{4}\)

\(\frac{63}{315}=\frac{63:63}{315:63}=\frac{1}{5}\)

\(\frac{11}{132}=\frac{1}{12}\)

\(\frac{63}{91}=\frac{9}{13}\)

\(\frac{270}{450}=\frac{3}{5}\)

\(\frac{51}{680}=\frac{3}{40}\)

\(\frac{225}{315}=\frac{5}{7}\)

\(\frac{234}{1404}=\frac{1}{6}\)

\(\frac{11}{132}=\frac{11:11}{132:11}=\frac{1}{12}\)

\(\frac{63}{91}=\frac{63:7}{91:7}=\frac{9}{13}\)

\(\frac{270}{450}=\frac{270:90}{450:90}=\frac{3}{5}\)

\(\frac{51}{680}=\frac{51:17}{680:17}=\frac{3}{40}\)

\(\frac{225}{315}=\frac{225:45}{315:45}=\frac{5}{7}\)

\(\frac{234}{1404}=\frac{234:234}{1404:234}=\frac{1}{6}\)

\(\frac{3}{10}x\frac{5}{6}=4x\frac{7}{18}=\frac{14}{9}x\frac{9}{14}=1\)

kia là dấu nhân phải ko??

Nếu vậy ta có: (rút gọn từng cái rồi ráp lại cho dễ)

\(\frac{3}{10}\times\frac{5}{6}=\frac{1}{2}\times\frac{1}{2}=\frac{1}{4}\left(rutgoncheo\right)\)

\(\frac{7}{18}\times\frac{9}{14}=\frac{1}{2}\times\frac{1}{2}=\frac{1}{4}\left(rutgoncheo\right)\)

Ráp lại có: \(\frac{1}{4}\times\frac{1}{4}=\frac{1}{16}\)

54/12:64/12=27/32

56/45x54/51=112/85

56/20+58/21=584/105

21/78-12/78=3/26

a).27/32

b).336/305

c).584/105

d).3/26