Giải câu 3 trang 19 VNEN toán 5 tập 1

$5 \frac{2}{10} + 7 \frac{1}{10} = \frac{52}{10} + \frac{71}{10} = \frac{123}{10}$

$5 \frac{6}{7} - 3 \frac{5}{7} = \frac{41}{7} - \frac{26}{7} = \frac{15}{7}$

$8 \frac{3}{5} \times 2 \frac{6}{7} = \frac{43}{5} \times \frac{20}{7} = \frac{860}{35}$

$1 \frac{3}{10} : 5 \frac{7}{8} = \frac{13}{10} : \frac{47}{8} = \frac{13}{10} \times \frac{8}{47} = \frac{104}{470}$