Question

giúp mình bài 4 với

 

Answer 1

1.a\(\dfrac{2}{7}+\dfrac{3}{7}-\dfrac{4}{7}=\dfrac{1}{7}\)

Answer 2

c: \(=\dfrac{2}{5}+\dfrac{3}{7}+\dfrac{6}{35}+3=\dfrac{14+15+6}{35}+3=1+3=4\)