Question

Giúp mình câu a,b,c và đưa ra giải thích nhá Thank

Answer 1

a.\(\dfrac{7}{30}+\dfrac{-12}{37}+\dfrac{23}{30}+\dfrac{-25}{37}=\left(\dfrac{7}{30}+\dfrac{23}{30}\right)+\left(\dfrac{-12}{37}+\dfrac{-25}{37}\right)=3-1=2\)

b.\(\dfrac{1}{2}+\dfrac{13}{19}-\dfrac{4}{9}+\dfrac{6}{19}+\dfrac{5}{18}=\left(\dfrac{13}{19}+\dfrac{6}{19}\right)+\left(\dfrac{-4}{9}+\dfrac{5}{18}\right)+\dfrac{1}{2}=1-\dfrac{1}{6}+\dfrac{1}{2}=1-\dfrac{1}{3}=\dfrac{2}{3}\)

c.\(\dfrac{-20}{23}+\dfrac{2}{3}-\dfrac{3}{23}+\dfrac{2}{5}+\dfrac{7}{15}=\left(\dfrac{-20}{23}-\dfrac{3}{23}\right)+\left(\dfrac{2}{3}+\dfrac{7}{15}\right)-\dfrac{3}{23}=-1+\dfrac{17}{15}-\dfrac{3}{23}=\dfrac{1}{345}\)