Tính: 2/3+4/3

Giải Toán lớp 4 Bài 90: Em ôn lại những gì đã học

Giải Toán lớp 4 Tập 2 trang 85 Bài 2:Tính:

a) $\frac{2}{3}+\frac{4}{3}$	$\frac{9}{8}-\frac{1}{8}$	$\frac{1}{6}+\frac{2}{3}$	$\frac{3}{4}-\frac{7}{16}$
b) $9+\frac{2}{7}$	$\frac{3}{8}+10$	$7-\frac{2}{11}$	$\frac{25}{4}-5$
c) $\frac{2}{3}\times \frac{1}{4}$	$\frac{7}{11}\times \frac{11}{2}$	$\frac{3}{7}:\frac{4}{9}$	$\frac{9}{8}:\frac{3}{4}$
d) $8\times \frac{3}{7}$	$\frac{3}{10}\times 6$	$6:\frac{5}{24}$	$\frac{18}{7}:3$

Lời giải:

a) $\frac{2}{3}+\frac{4}{3}=\frac{6}{3}=2$

$\frac{9}{8}-\frac{1}{8}=\frac{8}{8}=1$

$\frac{1}{6}+\frac{2}{3}=\frac{1}{6}+\frac{4}{6}=\frac{5}{6}$

$\frac{3}{4}-\frac{7}{16}=\frac{12}{16}-\frac{7}{16}=\frac{5}{16}$

b) $9+\frac{2}{7}=\frac{63}{7}+\frac{2}{7}=\frac{65}{7}$

$\frac{3}{8}+10=\frac{3}{8}+\frac{80}{8}=\frac{83}{8}$

$7-\frac{2}{11}=\frac{77}{11}-\frac{2}{11}=\frac{75}{11}$

$\frac{25}{4}-5=\frac{25}{4}-\frac{20}{4}=\frac{5}{4}$

c) $\frac{2}{3}\times \frac{1}{4}=\frac{2}{12}=\frac{1}{6}$

$\frac{7}{11}\times \frac{11}{2}=\frac{77}{22}=\frac{7}{2}$

$\frac{3}{7}:\frac{4}{9}=\frac{3}{7}\times \frac{9}{4}=\frac{27}{28}$

$\frac{9}{8}:\frac{3}{4}=\frac{9}{8}\times \frac{4}{3}=\frac{36}{24}=\frac{3}{2}$

d) $8\times \frac{3}{7}=\frac{8}{1}\times \frac{3}{7}=\frac{24}{7}$

$\frac{3}{10}\times 6=\frac{3}{10}\times \frac{6}{1}=\frac{18}{10}=\frac{9}{5}$

$6:\frac{5}{24}=\frac{6}{1}\times \frac{24}{5}=\frac{144}{5}$

$\frac{18}{7}:3=\frac{18}{7}\times \frac{1}{3}=\frac{18}{21}=\frac{6}{7}$