$\frac{1}{2}$ is 5 tienden ; $\frac{1}{5}$ is 2 tienden

$\frac{1}{2} + \frac{1}{5} = \frac{5}{10} + \frac{2}{10} = \frac{7}{10}$

In 14 stukjes.

$\frac{1}{2}$ is 7 veertienden ; $\frac{1}{7}$ is 2 veertienden

$\frac{1}{2} + \frac{1}{7} = \frac{7}{14} + \frac{2}{14} = \frac{9}{14}$

In 6 stukjes.

$\frac{2}{3} + \frac{1}{12} = \frac{8}{12} + \frac{1}{12} = \frac{9}{12} = \frac{3}{4}$	$\frac{p}{5} + \frac{1}{2} = \frac{2 p}{10} + \frac{5}{10} = \frac{2 p + 5}{10}$
$\frac{3}{7} - \frac{1}{4} = \frac{12}{28} - \frac{7}{28} = \frac{5}{28}$	$\frac{1}{5} - \frac{1}{7} = \frac{7}{35} - \frac{5}{35} = \frac{2}{35}$
$\frac{1}{2} - \frac{1}{4} + \frac{1}{5} = \frac{10}{20} - \frac{5}{20} + \frac{4}{20} = \frac{9}{20}$	$\frac{4}{5} - \frac{3}{7} = \frac{28}{35} - \frac{15}{35} = \frac{13}{35}$
$\frac{2}{5} + \frac{1}{2} = \frac{4}{10} + \frac{5}{10} = \frac{9}{10}$	$\frac{3}{5} - \frac{q}{7} = \frac{21}{35} - \frac{5 q}{35} = \frac{21 - 5 q}{35}$
$\frac{4}{5} + \frac{1}{2} = \frac{8}{10} + \frac{5}{10} = \frac{13}{10} = 1 \frac{3}{10}$

$\frac{1}{2} + \frac{1}{3} + \frac{1}{12} = \frac{6}{12} + \frac{4}{12} + \frac{1}{12} = \frac{11}{12}$ . Klopt.

$\frac{1}{4} + \frac{1}{8}$	$\frac{1}{2} + \frac{1}{5} + \frac{1}{10}$
$\frac{1}{3} + \frac{1}{9}$	$\frac{1}{2} + \frac{1}{5} + \frac{1}{30}$

$\frac{a}{3} + \frac{a}{9} = \frac{3 a}{9} + \frac{a}{9} = \frac{4 a}{9}$	$\frac{3}{a} + \frac{9}{a} = \frac{12}{a}$
$\frac{5 a}{6} + \frac{a}{9} = \frac{15 a}{18} + \frac{2 a}{18} = \frac{17 a}{18}$	$\frac{3}{a} + \frac{2}{5} = \frac{15}{5 a} + \frac{2 a}{5 a} = \frac{15 + 2 a}{5 a}$
$\frac{a}{3} - \frac{2 a}{9} = \frac{3 a}{9} - \frac{2 a}{9} = \frac{a}{9}$	$\frac{3 a}{a} - \frac{1}{2} = 3 - \frac{1}{2} = 2 \frac{1}{2}$
$\frac{4 a}{3} - \frac{5 a}{9} = \frac{12 a}{9} - \frac{5 a}{9} = \frac{7 a}{9}$	$\frac{2}{7} - \frac{1}{a} = \frac{2 a}{7 a} - \frac{7}{7 a} = \frac{2 a - 7}{7 a}$

$\frac{1}{8} - \frac{1}{32} = \frac{4}{32} - \frac{1}{32} = \frac{3}{32}$

$\frac{1}{4} + \frac{1}{16} + \frac{1}{64} + \frac{1}{256} = \frac{64}{256} + \frac{16}{256} + \frac{4}{256} + \frac{1}{256} = \frac{85}{256}$

$\frac{1}{2} + \frac{1}{8} + \frac{1}{32} = \frac{16}{32} + \frac{4}{32} + \frac{1}{32} = \frac{21}{32}$