Question

Find the difference:

(i) $\frac{5}{7}-\frac{2}{7}$
(ii) $\frac{5}{6}-\frac{3}{4}$
(iii) $3\frac{1}{5}-\frac{7}{10}$
(iv) $7-4\frac{2}{3}$
(v) $3\frac{3}{10}-1\frac{7}{15}$
(vi) $2\frac{5}{9}-1\frac{7}{15}$

Answer 1

(i) $\frac{5}{7}-\frac{2}{7}=\frac{5-2}{7}=\frac{3}{7}$

(ii) $\frac{5}{6}-\frac{3}{4}$

$=\frac{10}{12}-\frac{9}{12}$ [∵ LCM of 6 and 4 = 12]

= $\frac{10-9}{12}$

= $\frac{1}{12}$

(iii) $3\frac{1}{5}-\frac{7}{10}$

= $\frac{16}{5}-\frac{7}{10}$

= $\frac{32}{10}-\frac{7}{10}$ [∵ LCM of 5 and 10 = 10]

= $\frac{32-7}{10}$

= $\frac{25}{10}=\frac{5}{2}=2\frac{1}{2}$

(iv) $7-4\frac{2}{3}$

= $\frac{7}{1}-\frac{14}{3}$

= $\frac{21-14}{3}$ [∵ LCM of 1 and 3 = 3]

= $\frac{7}{3}=2\frac{1}{3}$

(v) $3\frac{3}{10}-1\frac{7}{15}$

= $\frac{33}{10}-\frac{22}{15}$

= $\frac{99-44}{30}$ [∵ LCM of 10 and 15 = 30]

= $\frac{55}{30}=\frac{11}{6}=1\frac{5}{6}$

(vi) $2\frac{5}{9}-1\frac{7}{15}$

= $\frac{23}{9}-\frac{22}{15}$

= $\frac{115-66}{45}$ [∵ LCM of 9 and 15 = 45]

=$\frac{49}{45}=1\frac{4}{45}$