cần giải thích theo để bài cô giao thêm
\(a,\dfrac{1}{3}=\dfrac{1.2}{3.2}=\dfrac{2}{6}\)
Ta có 2 < 5
=> \(\dfrac{1}{3}< \dfrac{5}{6}\)
b, \(\dfrac{4}{5}=\dfrac{4.7}{5.7}=\dfrac{28}{35}\\ \dfrac{3}{7}=\dfrac{3.5}{5.7}=\dfrac{15}{35}\)
mà 28 > 15
=> \(\dfrac{4}{5}>\dfrac{3}{7}\)
c, \(-\dfrac{3}{11}=\dfrac{-3.13}{143}=\dfrac{-39}{143}\\ -\dfrac{4}{13}=\dfrac{-4.11}{143}=\dfrac{-44}{143}\)
mà -39 > -44
=> \(-\dfrac{3}{11}>-\dfrac{4}{13}\)
\(\dfrac{1}{3};\dfrac{5}{6}\)
\(\text{MSC : 6}\)
\(\dfrac{1}{3}=\dfrac{1\times2}{3\times2}=\dfrac{2}{6}\)\(;\dfrac{5}{6}\)
vậy \(\dfrac{1}{3}< \dfrac{5}{6}\)
\(-------------------\)
\(\dfrac{4}{5};\dfrac{3}{7}\)
\(\text{MSC : 35
}\)
\(\dfrac{4}{5}=\dfrac{4\times7}{5\times7}=\dfrac{28}{35}\)
\(\dfrac{3}{7}=\dfrac{3\times5}{7\times5}=\dfrac{15}{35}\)
vậy \(\dfrac{4}{5}>\dfrac{3}{7}\)
\(-------------------\)
\(\text{MSC : 143}\)
\(\dfrac{-3}{11}=\dfrac{-3\times13}{143}=\dfrac{-39}{143}\)
\(\dfrac{-4}{13}=\dfrac{-4\times11}{143}=\dfrac{-44}{143}\)
vậy \(\dfrac{-3}{11}>\dfrac{-4}{13}\)
*) \(\dfrac{1}{3}=\dfrac{1.2}{3.2}=\dfrac{2}{6}\)
Do 2 < 5 nên \(\dfrac{2}{6}< \dfrac{5}{6}\)
Vậy \(\dfrac{1}{3}< \dfrac{5}{6}\)
*) \(\dfrac{4}{5}=\dfrac{4.7}{5.7}=\dfrac{28}{35}\)
\(\dfrac{3}{7}=\dfrac{3.5}{7.5}=\dfrac{15}{35}\)
Do 28 > 15 nên \(\dfrac{28}{35}>\dfrac{15}{35}\)
Vậy \(\dfrac{4}{5}>\dfrac{3}{7}\)
*) \(\dfrac{-3}{11}=\dfrac{-3.13}{11.13}=\dfrac{-39}{143}\)
\(\dfrac{-4}{13}=\dfrac{-4.11}{13.11}=\dfrac{-44}{143}\)
Do \(-39>-44\) nên \(\dfrac{-39}{143}>\dfrac{-44}{143}\)
Vậy \(\dfrac{-3}{11}>\dfrac{-4}{13}\)
