Question

Answer 1

\(\dfrac{4}{13}-\dfrac{8}{21}+\dfrac{9}{13}+\dfrac{-13}{21}\\ =\left(\dfrac{4}{13}+\dfrac{9}{13}\right)-\left(\dfrac{8}{21}-\dfrac{-13}{21}\right)\\ =\dfrac{13}{13}-\dfrac{21}{21}\\ =1-1\\ =0\)

Answer 2

\(\dfrac{4}{13}-\dfrac{8}{21}+\dfrac{9}{13}+\dfrac{-13}{21}=\left(\dfrac{4}{13}+\dfrac{9}{13}\right)-\left(\dfrac{8}{21}+\dfrac{13}{21}\right)=1-1=0\)

Answer 3

\(\left(\dfrac{4}{13}+\dfrac{9}{13}\right)+\left(\dfrac{-8}{21}+\dfrac{-13}{21}\right)=1+\left(-1\right)=0\)

Answer 4

=0

Answer 5

= 0