bài 3 :
a)\(\dfrac{1}{3}và\dfrac{1}{2}\)
ta có \(\dfrac{1}{3}=\dfrac{2}{6}\)
\(\dfrac{1}{2}=\dfrac{3}{6}\)
vì 2<3
-> \(\dfrac{2}{6}< \dfrac{3}{6}\)
->\(\dfrac{1}{3}< \dfrac{1}{2}\)
b)\(\dfrac{11}{12}và\dfrac{-12}{11}\)
vì \(\dfrac{11}{12}>0\)
\(\dfrac{-12}{11}< 0\)
->\(\dfrac{11}{12}>\dfrac{-12}{11}\)
c)\(\dfrac{-7}{8}và\dfrac{-5}{6}\)
\(tacó\dfrac{-7}{8}=\dfrac{-42}{48}\)
\(\dfrac{-5}{6}=\dfrac{-40}{48}\)
vì -42<-40
->\(\dfrac{-42}{48}< \dfrac{-40}{48}\)
\(->\dfrac{-7}{8}< \dfrac{-5}{6}\)
d) ta có \(\dfrac{-3}{-6}=\dfrac{3}{6}=\dfrac{1}{2}\)
\(\dfrac{4}{8}=\dfrac{1}{2}\)
vì 1=1 (cùng mẫu số )
->\(\dfrac{1}{2}=\dfrac{1}{2}\)
->\(\dfrac{4}{8}=\dfrac{-3}{-6}\)
