Thực hiện phép tính :
a, $\frac{3}{5}$ + $\frac{-5}{9}$
b, $\frac{4}{13}$ + $\frac{-12}{39}$
c, $\frac{8}{40}$ + $\frac{-36}{45}$
d, $\frac{7}{21}$ + $\frac{-9}{39}$
giúpp tớ đi :<<
Thực hiện phép tính :
a, $\frac{3}{5}$ + $\frac{-5}{9}$
b, $\frac{4}{13}$ + $\frac{-12}{39}$
c, $\frac{8}{40}$ + $\frac{-36}{45}$
d, $\frac{7}{21}$ + $\frac{-9}{39}$
giúpp tớ đi :<<
a, $\frac{3}{5}$ + $\frac{-5}{9}$
= $\frac{27}{45}$ – $\frac{25}{45}$
= $\frac{2}{45}$
b. $\frac{4}{13}$ + $\frac{-12}{39}$
= $\frac{4}{13}$ – $\frac{4}{13}$
= 0
c. $\frac{8}{40}$ + $\frac{-36}{45}$
= $\frac{1}{5}$ – $\frac{4}{5}$
= $\frac{-3}{5}$
d. $\frac{7}{21}$ + $\frac{-9}{39}$
= $\frac{1}{3}$ – $\frac{3}{13}$
= $\frac{13}{39}$ – $\frac{10}{39}$
Cho mk xin hay nhất