Question

a              2/3+5/9-3/4=                                b              2/7:2/3                  c              2/5 nhân 1/4:3/8                    

Answer 1

\(a.\frac{2}{3}+\frac{5}{9}-\frac{3}{4}=\frac{2\cdot12}{36}+\frac{5\cdot4}{36}-\frac{3\cdot9}{36}\)

\(=\frac{24+20-27}{36}=\frac{17}{36}\)

\(b.\frac{2}{7}:\frac{2}{3}=\frac{2}{7}\cdot\frac{3}{2}=\frac{1}{7}\cdot\frac{3}{1}=\frac{3}{7}\)

\(\frac{2}{5}\cdot\frac{1}{4}:\frac{5}{8}=\frac{1\cdot1}{5\cdot2}:\frac{5}{8}\)

\(=\frac{1}{10}:\frac{5}{8}=\frac{1}{10}\cdot\frac{8}{5}=\frac{1\cdot4}{5\cdot5}=\frac{4}{25}\)

Answer 2

a)\(=\frac{24+20+27}{36}=\frac{71}{36}\)

b)=\(\frac{2}{7}x\frac{3}{2}=\frac{3}{7}x1=\frac{3}{7}\)

c)\(\frac{2}{5}x\left(\frac{1}{4}:\frac{3}{8}\right)=\frac{2}{5}x\frac{2}{3}=\frac{4}{15}\)

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