Question

Tính:

a) \(\dfrac{3}{8}+\dfrac{7}{8}\)                          b) \(\dfrac{7}{9}-\dfrac{4}{9}\)                      c) \(\dfrac{5}{6}+\dfrac{1}{8}\)                       d) \(\dfrac{9}{15}-\dfrac{2}{5}\)

e) \(\dfrac{2}{5}+\dfrac{3}{5}+\dfrac{9}{5}\)                  g) \(\dfrac{8}{10}-\dfrac{1}{10}-\dfrac{3}{10}\)                  h) \(\dfrac{23}{7}-\dfrac{4}{7}+\dfrac{2}{7}\)

Answer 1

a: \(\dfrac{3}{8}+\dfrac{7}{8}=\dfrac{3+7}{8}=\dfrac{10}{8}=\dfrac{5}{4}\)

b: \(\dfrac{7}{9}-\dfrac{4}{9}=\dfrac{7-4}{9}=\dfrac{3}{9}=\dfrac{1}{3}\)

c: \(\dfrac{5}{6}+\dfrac{1}{8}=\dfrac{20}{24}+\dfrac{3}{24}=\dfrac{20+3}{24}=\dfrac{23}{24}\)

d: \(\dfrac{9}{15}-\dfrac{2}{5}=\dfrac{3}{5}-\dfrac{2}{5}=\dfrac{3-2}{5}=\dfrac{1}{5}\)

e: \(\dfrac{2}{5}+\dfrac{3}{5}+\dfrac{9}{5}=\dfrac{2+3+9}{5}=\dfrac{14}{5}\)

g: \(\dfrac{8}{10}-\dfrac{1}{10}-\dfrac{3}{10}=\dfrac{8-1-3}{10}=\dfrac{4}{10}=\dfrac{2}{5}\)

h: \(\dfrac{23}{7}-\dfrac{4}{7}+\dfrac{2}{7}=\dfrac{23-4+2}{7}=\dfrac{21}{7}=3\)