Question

Tính

A.1/4 + 3/8 

B. 5/12 + 7/3

C. 3/16 + 9/4

D.9 / 14 - 4/7

e. 2/5 - 4/15

G.8/7 - 10/21

Answer 1

a: \(\dfrac{1}{4}+\dfrac{3}{8}=\dfrac{2}{8}+\dfrac{3}{8}=\dfrac{5}{8}\)

b: \(\dfrac{5}{12}+\dfrac{7}{3}=\dfrac{5}{12}+\dfrac{28}{12}=\dfrac{5+28}{12}=\dfrac{33}{12}=\dfrac{11}{4}\)

c: \(\dfrac{3}{16}+\dfrac{9}{4}=\dfrac{3}{16}+\dfrac{36}{16}=\dfrac{3+36}{16}=\dfrac{39}{16}\)

d: \(\dfrac{9}{14}-\dfrac{4}{7}=\dfrac{9}{14}-\dfrac{8}{14}=\dfrac{1}{14}\)

e: \(\dfrac{2}{5}-\dfrac{4}{15}=\dfrac{6}{15}-\dfrac{4}{15}=\dfrac{2}{15}\)

g: \(\dfrac{8}{7}-\dfrac{10}{21}=\dfrac{8\cdot3-10}{21}=\dfrac{14}{21}=\dfrac{2}{3}\)