A. Hoạt động thực hànhCâu 1: Trang 22 VNEN toán lớp 5 tập 1Tính:

a.
Cách 1:
$\frac{7}{8} - \frac{1}{3} = \frac{21}{24} - \frac{8}{24} = \frac{13}{24}$

$\frac{8}{9} + \frac{2}{5}= \frac{40}{45} + \frac{18}{45} = \frac{58}{45}$

$\frac{3}{10}\times \frac{1}{6} = \frac{3\times 1}{10\times 6} = \frac{3}{60}=\frac{1}{20}$

$\frac{8}{9} : \frac{3}{7} = \frac{8}{9}\times \frac{7}{3} = \frac{56}{27}$

Cách 2:
$\frac{7}{8} - \frac{1}{3} = \frac{21}{24} - \frac{8}{24} = \frac{13}{24}$

$\frac{8}{9} + \frac{2}{5}= \frac{8\times 5 + 2 \times 9}{9\times 5} = \frac{40 + 18}{45} = \frac{58}{45}$

$\frac{3}{10}\times \frac{1}{6} = \frac{3\times 1}{10\times 6} = \frac{3}{60}=\frac{1}{20}$

$\frac{8}{9} : \frac{3}{7} = \frac{8}{9}\times \frac{7}{3} = \frac{56}{27}$

Câu trả lời cho câu hỏi trên là:
a. $\frac{7}{8} - \frac{1}{3} = \frac{13}{24}$; $\frac{8}{9} + \frac{2}{5}= \frac{58}{45}$; $\frac{3}{10} \times \frac{1}{6} = \frac{1}{20}$; $\frac{8}{9} : \frac{3}{7} = \frac{56}{27}$

b.
Cách 1:
$1\frac{2}{7} + 6\frac{5}{6}=\frac{9}{7} + \frac{41}{6} = \frac{54}{42} + \frac{287}{42} = \frac{341}{42}$

$5\frac{3}{4} - \frac{1}{5} = \frac{23}{4} - \frac{1}{5} = \frac{115}{20} - \frac{4}{20} = \frac{111}{20}$

$6\frac{2}{9} : 4\frac{7}{10} = \frac{56}{9} : \frac{47}{10} = \frac{56}{9} \times \frac{10}{47} = \frac{560}{423}$

$\frac{5}{3} + \frac{3}{2} - \frac{7}{6} = \frac{10}{6} + \frac{9}{6} - \frac{7}{6} = \frac{12}{6} = 2$

Cách 2:
$1\frac{2}{7} + 6\frac{5}{6}=\frac{9}{7} + \frac{41}{6} = \frac{54}{42} + \frac{287}{42} = \frac{341}{42}$

$5\frac{3}{4} - \frac{1}{5} = \frac{23}{4} - \frac{1}{5} = \frac{115}{20} - \frac{4}{20} = \frac{111}{20}$

$6\frac{2}{9} : 4\frac{7}{10} = \frac{56}{9} : \frac{47}{10} = \frac{56}{9} \times \frac{10}{47} = \frac{560}{423}$

$\frac{5}{3} + \frac{3}{2} - \frac{7}{6} = \frac{10}{6} + \frac{9}{6} - \frac{7}{6} = \frac{12}{6} = 2$

Câu trả lời cho câu hỏi trên là:
b. $1\frac{2}{7} + 6\frac{5}{6} = \frac{341}{42}$; $5\frac{3}{4} - \frac{1}{5} = \frac{111}{20}$; $6\frac{2}{9} : 4\frac{7}{10} = \frac{560}{423}$; $\frac{5}{3} + \frac{3}{2} - \frac{7}{6} = 2$