Question

tính hợp lí :2/7-3/11+5/7-8/11

 

Answer 1

\(\dfrac{2}{7}-\dfrac{3}{11}+\dfrac{5}{7}-\dfrac{8}{11}\\ =\left(\dfrac{2}{7}+\dfrac{5}{7}\right)-\left(\dfrac{3}{11}+\dfrac{8}{11}\right)\\ =\dfrac{7}{7}-\dfrac{11}{11}\\ =1-1\\ =0\)

Answer 2

= (2/7-5/7)+(3/11-8/11)

= 1 + (-1)

= 0

Answer 3

2/7-3/11+5/7-8/11

=0

Answer 4

 

    2/7-3/11+5/7-8/11

= (2/7-5/7)+(3/11-8/11)

= 1 + (-1)

= 0

Answer 5

= (2/7-5/7)+(3/11-8/11)

= 1 + (-1)

= 0