\(\frac{10}{18}+\frac{4}{9}+\frac{26}{10}+\frac{12}{5}+\frac{9}{15}\)

\(=\frac{5}{9}+\frac{4}{9}+\frac{13}{5}+\frac{12}{5}+\frac{3}{5}\)

\(=\left(\frac{5}{9}+\frac{4}{9}\right)+\left(\frac{13}{5}+\frac{12}{5}+\frac{3}{5}\right)\)

\(=1+\frac{28}{5}\)

\(=\frac{33}{5}\)

Ta có:

a) \(\frac{10}{18}+\frac{4}{9}+\frac{26}{10}+\frac{12}{5}+\frac{9}{15}=\frac{5}{9}+\frac{4}{9}+\frac{13}{5}+\frac{12}{5}+\frac{9}{15}=1+1+\frac{9}{15}=1\frac{9}{15}\)

b)\(\frac{10}{18}+\frac{4}{9}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}=\left(\frac{5}{9}+\frac{4}{9}\right)+\left(\frac{16}{128}+\frac{8}{128}+\frac{4}{128}+\frac{2}{128}+\frac{1}{128}\right)\)

\(=1+\frac{31}{128}=1\frac{31}{128}\)

Dễ mà  

Tự nghĩ đi bn

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3 chữ

thử đoán xem

a)\(\frac{77}{24}\)=\(3\frac{5}{24}\)

b)=10

c)\(\frac{24}{35}\)

=143/135

a)\(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+3\)

\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)

\(=1+\left(\frac{4}{9}+\frac{3}{9}\right)+3\)

\(=1+\frac{7}{9}+3\)

\(=1+3+\frac{7}{9}\)

\(=4\frac{7}{9}\)

\(=\frac{43}{9}\)

b)\(\frac{8}{5}\cdot\frac{4}{7}+\frac{4}{7}\cdot\frac{2}{5}-1\)

\(=\frac{4}{7}\cdot\left(\frac{8}{5}+\frac{2}{5}\right)-1\)

\(=\frac{4}{7}\cdot2-1\)

\(=\frac{8}{7}-1\)

\(=\frac{1}{7}\)

a) \(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+3\)

\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{3}{9}\right)+3\)

\(=1+\frac{7}{9}+3=4\frac{7}{9}\)

b)\(\frac{8}{5}.\frac{4}{7}+\frac{4}{7}.\frac{2}{5}-1\)

\(=\frac{4}{7}.\left(\frac{8}{5}+\frac{2}{5}\right)-1\)

\(=\frac{4}{7}.2-1\)

\(=\frac{8}{7}-\frac{7}{7}=\frac{1}{7}\)

\(8\frac{7}{12}-5\frac{3}{8}=\frac{8.12+7}{12}-\frac{5.8+3}{8}=\frac{103}{12}-\frac{43}{8}=\frac{77}{24}\)

\(2\frac{9}{13}.3\frac{5}{7}=\frac{2.13+9}{13}.\frac{3.7+5}{7}=\frac{35}{13}.15=\frac{525}{13}\)

\(3\frac{19}{35}:5\frac{7}{42}=\frac{3.35+19}{35}:\frac{5.42+7}{42}=\frac{124}{35}:\frac{31}{6}=\frac{124}{35}.\frac{6}{31}=\frac{24}{35}\)