Giải câu 2 trang 13 VBT toán 5 tập 1

a) $2\frac{1}{8}$ + $1\frac{3}{4}$ = $\frac{17}{8}$ + $\frac{7}{4}$ = $\frac{17}{8}$ + $\frac{14}{8}$ = $\frac{31}{8}$

$3\frac{2}{7}$ + $1\frac{3}{7}$ = $\frac{23}{7}$ + $\frac{10}{7}$ = $\frac{33}{7}$

b) $5\frac{1}{3}$ - 2$\frac{5}{6}$ = $\frac{16}{3}$ - $\frac{17}{6}$ = $\frac{32}{6}$ - $\frac{17}{6}$ = $\frac{15}{6}$ = $\frac{5}{2}$

$4\frac{7}{9}$ - $1\frac{5}{9}$ = $\frac{43}{9}$ - $\frac{14}{9}$ = $\frac{29}{9}$

c) $2\frac{4}{5}$ x $3\frac{1}{8}$ = $\frac{14}{5}$ x $\frac{25}{8}$ = $\frac{7\times \not{2}\times \not{5}\times 5}{\not{5}\times 4\times \not{2}}$ = $\frac{35}{4}$

$1\frac{1}{5}$ : $1\frac{4}{5}$ = $\frac{6}{5}$ : $\frac{9}{5}$ = $\frac{6}{5}$ x $\frac{5}{9}$ = $\frac{30}{45}$ = $\frac{2}{3}$