Giải bài 1 trang 24 toán 7 tập 1 chân trời sáng tạo

a) $\left ( \frac{-3}{7}\right ) + \left ( \frac{5}{6} -\frac{4}{7} \right )$

= $\left ( \frac{-3}{7}\right ) + \left ( \frac{35}{42} -\frac{24}{42} \right )$

= $\left ( \frac{-3}{7}\right ) + \frac{11}{42}$

= $\left ( \frac{-18}{42}\right ) + \frac{11}{42}$

= $\frac{-1}{6}$

b) $\frac{3}{5} - \left ( \frac{2}{3} +\frac{1}{5} \right )$

= $\frac{3}{5} - \left ( \frac{10}{15} +\frac{3}{15} \right )$

= $\frac{3}{5} - \frac{13}{15} $

= $\frac{9}{15} - \frac{13}{15} $

= $\frac{-4}{15}$

c) $\left [ \left ( \frac{-1}{3}\right ) + 1 \right ] - \left ( \frac{2}{3} -\frac{1}{5}\right )$

= $\left [ \left ( \frac{-1}{3}\right ) + \frac{3}{3} \right ] - \left ( \frac{10}{15} -\frac{3}{15}\right )$

= $\frac{2}{3} - \frac{7}{15}$

= $\frac{10}{15} - \frac{7}{15}$

= $\frac{1}{5}$

d) $1\frac{1}{3} + \left (\frac{2}{3} -\frac{3}{4}  \right ) - \left ( 0,8 + 1\frac{1}{5} \right )$

= $\frac{4}{3} + \left (\frac{8}{12} -\frac{9}{12}  \right ) - \left ( \frac{4}{5} + \frac{6}{5} \right )$

=  $\frac{4}{3} -\frac{1}{12}  - 2$

= $\frac{16}{12} -\frac{1}{12}  - \frac{24}{12}$

= $-\frac{9}{12}$

= $-\frac{3}{4}$