Question

2. So sánh các phân số sau bằng cách hợp lý nhất :

a ) \(\frac{5}{6}\)và \(\frac{15}{18}\)

b) \(\frac{99}{100}\)và \(\frac{100}{99}\)

c) \(\frac{15}{17}\)và \(\frac{13}{18}\)

d) \(\frac{222}{333}\)và \(\frac{333}{444}\)

e) \(\frac{292929}{272727}\)và \(\frac{347347}{345345}\)

Answer 1

a) \(\frac{5}{6}\)= \(\frac{15}{18}\); b)  \(\frac{99}{100}\)< \(\frac{100}{99}\);   c ) \(\frac{15}{17}\)> \(\frac{13}{18}\)vì \(\frac{15}{17}\)> \(\frac{15}{18}\)> \(\frac{13}{18}\); 

d) \(\frac{222}{333}\)= \(\frac{2}{3}\)\(=1-\frac{1}{3}\); \(\frac{3333}{4444}\)= \(\frac{3}{4}\)= \(1-\frac{1}{4}\); vì \(\frac{1}{3}\)> \(\frac{1}{4}\)nên \(\frac{222}{333}\)< \(\frac{3333}{4444}\)

e) \(\frac{292929}{272727}\)= \(\frac{29}{27}\)= \(1+\frac{2}{17}\); \(\frac{347347}{345345}\)= \(\frac{347}{345}\)= \(1+\frac{2}{345}\)nên \(\frac{292929}{272727}\)> \(\frac{347347}{345345}\)