a) \(\dfrac{3}{4}+\dfrac{1}{5}=\dfrac{15}{20}+\dfrac{4}{20}=\dfrac{19}{20}\)
b)\(\dfrac{1}{36}+\dfrac{5}{12}=\dfrac{1}{36}+\dfrac{3}{36}=\dfrac{4}{36}=\dfrac{1}{9}\)
c)\(\dfrac{1}{8}+\dfrac{7}{10}=\dfrac{10}{80}+\dfrac{56}{80}=\dfrac{66}{80}=\dfrac{33}{40}\)
d)\(\dfrac{1}{8}+\dfrac{5}{6}=\dfrac{6}{48}+\dfrac{40}{48}=\dfrac{49}{48}=\dfrac{23}{24}\)
bài 1 :
a) = 13/12
b) = 7/18
d) = 37/40
e) = 17/24
bài 2 :
a) = 19/20
b) = 4/9
d) = 33/40
e) = 23/24
bài 3:
a) = 1/4 + 5/6 = 13/12
b) =1/8 + 3/4 =7/8
c) 1/4 + 1/5 = 9/20
d) = 2/3 + 2/7 = 20/21
Bài 1
a) \(\dfrac{1}{4}+\dfrac{5}{6}=\dfrac{3}{12}+\dfrac{10}{12}=\dfrac{13}{12}\)
b) \(\dfrac{2}{9}+\dfrac{1}{6}=\dfrac{4}{18}+\dfrac{3}{18}=\dfrac{7}{18}\)
d) \(\dfrac{3}{10}+\dfrac{5}{8}=\dfrac{12}{40}+\dfrac{25}{40}=\dfrac{37}{40}\)
e) \(\dfrac{7}{12}+\dfrac{1}{8}=\dfrac{14}{24}+\dfrac{3}{24}=\dfrac{17}{24}\)
Tính tổng
a) \(\dfrac{3}{4}+\dfrac{1}{5}=\dfrac{15}{20}+\dfrac{4}{20}=\dfrac{19}{20}\)
b) \(\dfrac{1}{36}+\dfrac{5}{12}=\dfrac{1}{36}+\dfrac{15}{36}=\dfrac{16}{36}=\dfrac{4}{9}\)
d) \(\dfrac{1}{8}+\dfrac{7}{10}=\dfrac{5}{40}+\dfrac{28}{40}=\dfrac{33}{40}\)
e) \(\dfrac{1}{8}+\dfrac{5}{6}=\dfrac{3}{24}+\dfrac{20}{24}=\dfrac{23}{24}\)
Rút gọn rồi tính
a) \(\dfrac{2}{8}+\dfrac{5}{6}=\dfrac{1}{4}+\dfrac{5}{6}=\dfrac{3}{12}+\dfrac{10}{12}=\dfrac{13}{12}\)
b) \(\dfrac{1}{8}+\dfrac{12}{16}=\dfrac{1}{8}+\dfrac{3}{4}=\dfrac{2}{16}+\dfrac{12}{16}=\dfrac{14}{16}=\dfrac{7}{8}\)
c) \(\dfrac{1}{4}+\dfrac{6}{30}=\dfrac{1}{4}+\dfrac{1}{5}=\dfrac{5}{20}+\dfrac{4}{20}=\dfrac{9}{20}\)
d) \(\dfrac{12}{18}+\dfrac{12}{42}=\dfrac{2}{3}+\dfrac{2}{7}=\dfrac{14}{21}+\dfrac{6}{21}=\dfrac{20}{21}\)
e chỉ cần bài 1thôi ạ 
Tính giúp mình nha