Question

[lê thị hiền]

bài 1:tính

a)\(8\frac{7}{12}-5\frac{3}{8}=?\) b)\(2\frac{9}{13}x3\frac{5}{7}=?\) c)\(3\frac{19}{35}:5\frac{7}{42}=?\)

Answer 1

[Thanh Tùng DZ]

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

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

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