Question

so sánh phân số 

a/\(1\frac{7}{9}\)và\(\frac{34}{13}\)

b/\(\frac{7}{9}\)và\(\frac{13}{15}\)

Answer 1

a) \(\frac{34}{13}=2\frac{8}{13}\)

Vì 2 > 1 nên \(2\frac{8}{13}>1\frac{7}{9}\)

hay \(\frac{34}{13}>1\frac{7}{9}\)

b) \(\frac{7}{9}=1-\frac{2}{9}\)

\(\frac{13}{15}=1-\frac{2}{15}\)

Vì \(\frac{2}{9}>\frac{2}{15}\) nên \(\frac{7}{9}< \frac{13}{15}\)

Answer 2

a) Ta có:

\(1\frac{7}{9}=\frac{16}{9}=\frac{208}{117}\) 

\(\frac{34}{13}=\frac{306}{117}\)

Vì \(306>208\)

\(\Rightarrow\frac{306}{117}>\frac{208}{117}\)

\(\Rightarrow\frac{34}{13}>1\frac{7}{9}\)

b) Ta có:

\(\frac{7}{9}=\frac{35}{45}\)

\(\frac{13}{15}=\frac{39}{45}\)

Vì \(39>35\)

\(\Rightarrow\frac{39}{45}>\frac{35}{45}\)

\(\Rightarrow\frac{13}{15}>\frac{7}{9}\)