Bài tập ôn hè Toán 4 lên lớp 5 Dạng 4: Cộng, trừ, nhân, chia phân số có đáp án

$\frac{2}{7}+\frac{4}{7}=\frac{2+4}{7}=\frac{6}{7}$

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

$\frac{2}{9}+\frac{3}{9}=\frac{2+3}{9}=\frac{5}{9}$

$\frac{2}{3}+\frac{1}{5}=\frac{10}{15}+\frac{3}{15}=\frac{10+3}{15}=\frac{13}{15}$

$\frac{3}{7}+\frac{9}{14}=\frac{6}{14}+\frac{9}{14}=\frac{6+9}{14}=\frac{15}{14}$

$\frac{3}{5}+\frac{5}{6}=\frac{18}{30}+\frac{25}{30}=\frac{18+25}{30}=\frac{43}{30}$

$\frac{5}{12}+\frac{3}{4}=\frac{5}{12}+\frac{9}{12}=\frac{5+9}{12}=\frac{14}{12}=\frac{7}{6}$

$\frac{5}{8}+\frac{7}{24}=\frac{15}{24}+\frac{7}{24}=\frac{15+7}{24}=\frac{22}{24}=\frac{11}{12}$

$\frac{6}{5}+\frac{9}{30}=\frac{6}{5}+\frac{3}{10}=\frac{6}{50}+\frac{15}{50}$

$=\frac{60+15}{50}=\frac{75}{50}=\frac{3}{2}$

$\frac{7}{12}+\frac{5}{2}=\frac{7}{12}+\frac{30}{12}=\frac{7+30}{12}=\frac{37}{12}$

$\frac{9}{21}+\frac{6}{49}=\frac{3}{7}+\frac{6}{49}=\frac{21}{49}+\frac{6}{49}$

$=\frac{21+6}{49}=\frac{27}{49}$

$\frac{1}{8}+\frac{3}{8}+\frac{9}{8}=\frac{1+3+9}{8}=\frac{13}{8}$

$\frac{1}{20}+\frac{3}{4}+\frac{6}{5}=\frac{1}{20}+\frac{15}{20}+\frac{24}{20}$

$=\frac{1+15+24}{20}=\frac{40}{20}=2$

$\frac{3}{4}+\frac{1}{25}+\frac{3}{100}=\frac{75}{100}+\frac{4}{100}+\frac{1}{100}$

$=\frac{75+4+1}{100}=\frac{80}{100}=\frac{4}{5}$

$\frac{2}{75}+\frac{3}{25}+\frac{7}{5}=\frac{2}{75}+\frac{9}{75}+\frac{105}{75}$

$=\frac{2+9+105}{75}=\frac{116}{75}$

$\frac{4}{7}+\frac{11}{9}+\frac{10}{7}+\frac{7}{9}$

$=\left(\frac{4}{7}+\frac{10}{7}\right)+\left(\frac{11}{9}+\frac{7}{9}\right)$

$=\frac{4+10}{7}+\frac{11+7}{9}$

$=\frac{14}{7}+\frac{18}{9}=2+2=4$

$\frac{1}{6}+\frac{7}{12}+\frac{5}{6}+\frac{5}{12}$

$=\left(\frac{1}{6}+\frac{5}{6}\right)+\left(\frac{7}{12}+\frac{5}{12}\right)$

$=\frac{1+5}{6}+\frac{7+5}{12}$

$=\frac{6}{6}+\frac{12}{12}=1+1=2$

$\frac{1}{26}+\frac{7}{30}+\frac{12}{26}+\frac{8}{30}$

$=\left(\frac{1}{26}+\frac{12}{26}\right)+\left(\frac{7}{30}+\frac{8}{30}\right)$

$=\frac{1+12}{26}+\frac{7+8}{30}=\frac{13}{26}+\frac{15}{30}$

$=\frac{1}{2}+\frac{1}{2}=1$

$\frac{6}{25}+\frac{7}{48}+\frac{9}{25}+\frac{17}{48}$

$=\left(\frac{6}{25}+\frac{9}{25}\right)+\left(\frac{7}{48}+\frac{17}{48}\right)$

$=\frac{15}{25}+\frac{24}{48}=\frac{3}{5}+\frac{1}{2}$

$=\frac{6}{10}+\frac{5}{10}=\frac{6+5}{10}=\frac{11}{10}$

$\frac{1}{2}-\frac{3}{8}=\frac{4}{8}-\frac{3}{8}=\frac{4-3}{8}=\frac{1}{8}$

$\frac{3}{4}-\frac{5}{12}=\frac{9}{12}-\frac{5}{12}$

$=\frac{9-5}{12}=\frac{4}{12}=\frac{1}{3}$

$\frac{11}{24}-\frac{3}{8}=\frac{11}{24}-\frac{9}{24}$

$=\frac{11-9}{24}=\frac{2}{24}=\frac{1}{12}$

$\frac{29}{36}-\frac{9}{24}=\frac{29}{36}-\frac{3}{8}$

$=\frac{58}{72}-\frac{27}{72}=\frac{58-27}{72}=\frac{31}{72}$

$\frac{6}{12}-\frac{1}{15}=\frac{1}{2}-\frac{1}{15}$

$=\frac{15}{30}-\frac{2}{30}=\frac{15-2}{30}=\frac{13}{30}$

$\frac{4}{20}-\frac{1}{6}=\frac{1}{5}-\frac{1}{6}$

$=\frac{6}{30}-\frac{5}{30}=\frac{1}{30}$

$\frac{6}{24}-\frac{6}{36}=\frac{1}{4}-\frac{1}{6}=\frac{3}{12}-\frac{2}{12}$

$=\frac{3-2}{12}=\frac{1}{12}$

$\frac{8}{32}-\frac{9}{81}=\frac{1}{4}-\frac{1}{9}=\frac{9}{36}-\frac{4}{36}$

$=\frac{9-4}{36}=\frac{5}{36}$

$\frac{18}{35}-\frac{2}{5}+\frac{3}{7}$

$=\frac{18}{35}-\frac{14}{35}+\frac{15}{35}$

$=\frac{18-14+15}{35}=\frac{19}{35}$

$\frac{11}{12}-\frac{1}{3}-\frac{1}{4}=\frac{11}{12}-\frac{4}{12}-\frac{3}{12}$

$=\frac{11-4-3}{12}=\frac{4}{12}=\frac{1}{3}$

$\frac{9}{20}-\frac{1}{4}-\frac{1}{5}$

$=\frac{9}{20}-\frac{5}{20}-\frac{4}{20}$

$=\frac{9-5-4}{20}=\frac{0}{20}=0$

$\frac{2}{5}\times \frac{7}{9}=\frac{2\times 7}{5\times 9}=\frac{14}{45}$

$\frac{3}{8}\times \frac{11}{12}=\frac{3\times 11}{8\times 3\times 4}=\frac{11}{8\times 4}=\frac{11}{32}$

$\frac{6}{11}\times \frac{11}{6}=\frac{6\times 11}{11\times 6}=1$

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

$\frac{2}{3}\times \frac{3}{4}\times \frac{4}{5}=\frac{2\times 3\times 4}{3\times 4\times 5}=\frac{2}{5}$

$\frac{8}{9}\times \frac{9}{10}\times \frac{10}{11}=\frac{8\times 9\times 10}{9\times 10\times 11}=\frac{8}{11}$

$\frac{5}{24}\times \frac{12}{15}\times \frac{48}{12}=\frac{5\times 12\times 24\times 2}{24\times 3\times 5\times 12}=\frac{2}{3}$

$\frac{21}{8}\times \frac{16}{14}\times \frac{7}{2}\times \frac{8}{7}=\frac{21\times 16\times 7\times 8}{8\times 14\times 2\times 7}$

$=\frac{3\times 7\times 2\times 8\times 7\times 8}{8\times 2\times 7\times 2\times 7}=\frac{3\times 8}{2}=\frac{24}{2}=12$

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

$=\frac{2\times 2\times 3}{3\times 3\times 2}=\frac{2}{3}$

$\frac{32}{7}:\frac{8}{21}=\frac{32}{7}\times \frac{21}{8}=\frac{32\times 21}{7\times 8}$

$=\frac{4\times 8\times 3\times 7}{7\times 8}=4\times 3=12$

$\frac{16}{21}:\frac{32}{28}=\frac{16}{21}\times \frac{28}{32}=\frac{16\times 28}{21\times 32}$

$=\frac{2\times 8\times 4\times 7}{3\times 7\times 4\times 8}=\frac{2}{3}$

$\frac{18}{64}:\frac{9}{8}=\frac{18}{64}\times \frac{8}{9}=\frac{18\times 8}{64\times 9}$

$=\frac{2\times 9\times 8}{8\times 8\times 9}=\frac{2}{8}=\frac{1}{4}$

$\frac{2}{3}\times \frac{5}{2}:\frac{9}{5}=\frac{2}{3}\times \frac{5}{2}\times \frac{5}{9}$

$=\frac{2\times 5\times 5}{3\times 2\times 9}=\frac{5\times 5}{3\times 9}=\frac{25}{27}$

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

$=\frac{1}{12}+\frac{10}{12}=\frac{1+10}{12}=\frac{11}{12}$

$\frac{1}{2}-\frac{7}{8}:\frac{7}{4}=\frac{1}{2}-\frac{7}{8}\times \frac{4}{7}$

$=\frac{1}{2}-\frac{4}{8}=\frac{1}{2}-\frac{1}{2}=0$

$\frac{6}{5}-\frac{4}{5}\times \frac{3}{2}=\frac{6}{5}-\frac{2\times 3}{5}$

$=\frac{6}{5}-\frac{6}{5}=0$

$\frac{2}{5}\times \frac{25}{29}+\frac{3}{5}\times \frac{25}{29}=\frac{25}{29}\times \left(\frac{2}{5}+\frac{3}{5}\right)$

$=\frac{25}{29}\times 1=\frac{25}{29}$

$$\begin{gathered} \frac{5}{2}\times \frac{3}{7}-\frac{3}{14}:\frac{6}{7}=\frac{5\times 3}{2\times 7}-\frac{3}{14}\times \frac{7}{6} \\ =\frac{15}{14}-\frac{3\times 7}{2\times 7\times 2\times 3}=\frac{15}{14}-\frac{1}{2\times 2} \\ =\frac{15}{14}-\frac{1}{4}=\frac{30}{28}-\frac{7}{28}=\frac{30-7}{28}=\frac{23}{28} \end{gathered}$$

$\frac{15}{4}:\frac{5}{12}-\frac{6}{5}:\frac{11}{15}=\frac{15}{4}\times \frac{12}{5}-\frac{6}{5}\times \frac{15}{11}$

$=\frac{15}{5}\times \frac{12}{4}-\frac{6}{11}\times \frac{15}{5}=3\times 3-\frac{6}{11}\times 3$

$=9-\frac{18}{11}=\frac{99-18}{11}=\frac{81}{11}$

$\frac{2}{3}\times \frac{20}{21}\times \frac{3}{2}\times \frac{7}{5}=\frac{2\times 20\times 3\times 7}{3\times 21\times 2\times 5}$

$=\frac{2\times 2\times 10\times 21}{3\times 21\times 10}=\frac{2\times 2}{3}=\frac{4}{3}$

$\frac{5}{17}\times \frac{21}{32}\times \frac{47}{24}\times 0$

$=\left(\frac{5}{17}\times \frac{21}{32}\times \frac{47}{24}\right)\times 0=0$

$\frac{11}{3}\times \frac{26}{7}-\frac{26}{7}\times \frac{8}{3}=\frac{26}{7}\times \left(\frac{11}{3}-\frac{8}{3}\right)$

$=\frac{26}{7}\times \frac{11-8}{3}=\frac{26}{7}\times \frac{3}{3}=\frac{26}{7}$