a) \(\dfrac{2}{7}+\dfrac{9}{7}=\dfrac{2+9}{7}=\dfrac{11}{7}\)
b) \(\dfrac{5}{9}+\dfrac{7}{9}=\dfrac{5+7}{9}=\dfrac{12}{9}=\dfrac{4}{3}\)
c) \(\dfrac{12}{17}+\dfrac{5}{17}=\dfrac{12+5}{17}=\dfrac{17}{17}=1\)
d) \(\dfrac{5}{24}+\dfrac{5}{24}=\dfrac{5+5}{24}=\dfrac{10}{24}=\dfrac{5}{12}\)
e) \(\dfrac{-1}{10}+\dfrac{-1}{10}=\dfrac{\left(-1\right)+\left(-1\right)}{10}=\dfrac{-2}{10}=\dfrac{-1}{5}\)
f) \(\dfrac{2}{3}+\dfrac{5}{8}=\dfrac{16}{24}+\dfrac{15}{24}=\dfrac{31}{24}\)
g) \(\dfrac{5}{6}+\dfrac{-3}{4}=\dfrac{20}{24}+\dfrac{-18}{24}=\dfrac{-2}{24}=\dfrac{-1}{24}\)
h) \(\dfrac{-5}{12}+\dfrac{7}{8}=\dfrac{-40}{96}+\dfrac{84}{96}=\dfrac{44}{96}=\dfrac{11}{24}\)
i) \(\dfrac{-3}{6}+\dfrac{1}{8}=\dfrac{-24}{48}+\dfrac{6}{48}=\dfrac{-20}{48}=\dfrac{-5}{12}\)
j) \(\dfrac{-5}{18}+\dfrac{17}{36}=\dfrac{-10}{36}+\dfrac{17}{36}=\dfrac{7}{36}\)
k) \(\dfrac{8}{21}+\dfrac{-4}{7}=\dfrac{8}{21}+\dfrac{-12}{21}=\dfrac{10}{21}\)
m) \(\dfrac{7}{24}+\dfrac{-1}{12}=\dfrac{7}{24}+\dfrac{-1}{1}=\dfrac{7}{24}+\dfrac{-1}{24}=\dfrac{6}{24}=\dfrac{1}{4}\)
n) \(\dfrac{13}{30}+\dfrac{-7}{6}=\dfrac{13}{30}+\dfrac{-35}{30}=\dfrac{-22}{35}\)
o) \(\dfrac{-8}{11}+\dfrac{4}{55}=\dfrac{-88}{55}+\dfrac{4}{55}=\dfrac{-84}{55}\)
a) 11/7 b) 14/9 c) 1 d)5/12 e)-2/5 f)31/24 g)1/12 h)11/24 i)-5/24
j) -1/12 (thôi đủ rồi :)
p) \(\dfrac{17}{18}+\dfrac{-5}{54}=\dfrac{51}{54}+\dfrac{-5}{54}=\dfrac{46}{54}=\dfrac{23}{27}\)
q) \(4+\dfrac{-17}{9}=\dfrac{4}{1}+\dfrac{-17}{9}=\dfrac{36}{9}+\dfrac{-17}{9}=\dfrac{19}{9}\)
r) \(1+\dfrac{-3}{5}=\dfrac{1}{1}+\dfrac{-3}{5}=\dfrac{5}{5}+\dfrac{-3}{5}=\dfrac{2}{5}\)
Mấy câu tiếp bạn dựa những câu mình đã làm nhé , mỏi tay rồi
