Question

7supra20-5supra18
8supra13-5supra39

Answer 1

$a)\frac{7}{20} - \frac{5}{18} = \frac{7 \times 9}{20 \times 9} - \frac{5 \times 10}{18 \times 10} = \frac{63}{180} - \frac{50}{180} = \frac{63 - 50}{180} = \frac{13}{180}$

$b) \frac{8}{13} - \frac{5}{39} = \frac{8 \times 3}{13 \times 3} - \frac{5}{39} = \frac{24}{39} - \frac{5}{39} = \frac{24 - 5}{39} = \frac{19}{39}$