Question

[Nguyễn Công Đoàn]

thực hiện phép tính	so sánh với \(\dfrac{6}{9}\)\(\dfrac{2}{3}\)
\(\dfrac{2+3}{9+3}\)
\(\dfrac{6-2}{9-3}\)

thực hiện phép tính	so sánh với \(\dfrac{3}{5}\) \(\dfrac{12}{20}\)
\(\dfrac{3+12}{5+20}\)
\(\dfrac{3-12}{5-20}\)

Answer 1

[ChaosKiz]

\(1,\)\(a,\dfrac{2+3}{9+3}=\dfrac{5}{12}\)

\(\Leftrightarrow\dfrac{5}{12}=\dfrac{5.3}{12.3}=\dfrac{15}{36}\) và \(\dfrac{6}{9}=\dfrac{24}{36}\)

\(\dfrac{15}{36}< \dfrac{24}{36}\Rightarrow\dfrac{5}{12}< \dfrac{6}{9}\) hay \(\dfrac{2+3}{9+3}< \dfrac{6}{9}\)

\(\dfrac{2}{3}=\dfrac{8}{12}\Rightarrow\dfrac{5}{12}< \dfrac{2}{3}\) hay \(\dfrac{2+3}{9+3}< \dfrac{2}{3}\)

\(b,\dfrac{6-2}{9-3}=\dfrac{4}{6}=\dfrac{2}{3}\Rightarrow\dfrac{6-2}{9-3}=\dfrac{2}{3}\)

\(\dfrac{2}{3}=\dfrac{6}{9}\Rightarrow\dfrac{6-2}{9-3}=\dfrac{6}{9}\)

\(2,a,\dfrac{3+12}{5+20}=\dfrac{15}{25}=\dfrac{3}{5}\Rightarrow\dfrac{3+12}{5+20}=\dfrac{3}{5}\)

\(\dfrac{3}{5}=\dfrac{3.4}{5.4}=\dfrac{12}{20}\Rightarrow\dfrac{3+12}{5+20}=\dfrac{12}{20}\)

\(b,\dfrac{3-12}{5-20}=\dfrac{-9}{-15}=\dfrac{9}{15}=\dfrac{3}{5}\Rightarrow\dfrac{3-12}{5-20}=\dfrac{3}{5}\)

\(\dfrac{3}{5}=\dfrac{3.4}{5.4}=\dfrac{12}{20}\Rightarrow\dfrac{3-12}{5-20}=\dfrac{12}{20}\)

Answer 2

[Nguyễn Công Đoàn]

tks tks rất rất

nhiều