- Xin ctlhn
a) 1$\frac{4}{23}$ + $\frac{5}{21}$ - $\frac{4}{23}$ + $\frac{1}{2}$ + $\frac{16}{21}$
= ( 1$\frac{4}{23}$ - $\frac{4}{23}$ ) + ( $\frac{5}{21}$ + $\frac{16}{21}$ ) + $\frac{1}{2}$
= 1 + 1 + $\frac{1}{2}$
= 2$\frac{1}{2}$
b) $\frac{1}{7}$ . $\frac{-3}{8}$ + $\frac{1}{7}$ . $\frac{-13}{8}$
= $\frac{1}{7}$. ( $\frac{-3}{8}$ + $\frac{-13}{8}$ )
= $\frac{1}{7}$. (-2)
= $\frac{-2}{7}$
c) $\frac{3}{7}$ . 19$\frac{1}{3}$ - $\frac{3}{7}$ . 33$\frac{1}{3}$
= $\frac{3}{7}$. ( 19$\frac{1}{3}$ - 33$\frac{1}{3}$ )
= $\frac{3}{7}$. (-14 )
= -6
~ Chúc bn hok tốt ~
