Question

sắp xếp các phân sốtheo thứ tự tăng dần (phải giải thích )

\(\frac{21}{25}\) \(\frac{60}{81}\)\(\frac{19}{29}\)

Answer 1

\(\frac{21}{25}=\frac{1}{25}+\frac{20}{25}>\frac{20}{27}\)

\(=\frac{60}{81}>\frac{20}{29}\)

\(=\frac{19}{29}\)

Answer 2

Ta có:\(\frac{60}{81}\)=\(\frac{20}{27}\)

Quy đồng:

25=5²

27=3³

29=29

BCNN(25;27;29)=19575

\(\frac{21}{25}=\frac{21.783}{25.783}=\frac{16443}{19575}\)

\(\frac{20}{27}=\frac{20.725}{27.725}=\frac{14500}{19575}\)

\(\frac{19}{29}=\frac{19.675}{29.675}=\frac{12825}{19575}\)

Vì 12825<14500<16443=>\(\frac{19}{29}< \frac{20}{27}< \frac{21}{25}\)

Hay \(\frac{19}{29}\)\(< \frac{60}{81}< \frac{21}{25}\)