Question

add
(7) $\frac{1}{2}+\frac{1}{4}+\frac{1}{14}$
=
(8) $\frac{1}{2}+\frac{1}{8}+\frac{1}{16}$
=
(9) $\frac{1}{2}+\frac{1}{8}+\frac{1}{24}$
=
(10) $\frac{1}{6}+\frac{1}{9}+\frac{1}{18}$
=
(11) $\frac{1}{7}+\frac{1}{9}+\frac{1}{21}$
=
(12) $\frac{1}{5}+\frac{1}{8}+\frac{1}{16}$
=

Explanation:

(7)

Step1: Find common denominator (28)

$\frac{1}{2} + \frac{1}{4} + \frac{1}{14} = \frac{14}{28} + \frac{7}{28} + \frac{2}{28}$

Step2: Sum numerators

$\frac{14+7+2}{28} = \frac{23}{28}$

(8)

Step1: Find common denominator (16)

$\frac{1}{2} + \frac{1}{8} + \frac{1}{16} = \frac{8}{16} + \frac{2}{16} + \frac{1}{16}$

Step2: Sum numerators

$\frac{8+2+1}{16} = \frac{11}{16}$

(9)

Step1: Find common denominator (24)

$\frac{1}{2} + \frac{1}{8} + \frac{1}{24} = \frac{12}{24} + \frac{3}{24} + \frac{1}{24}$

Step2: Sum numerators

$\frac{12+3+1}{24} = \frac{16}{24} = \frac{2}{3}$

(10)

Step1: Find common denominator (18)

$\frac{1}{6} + \frac{1}{9} + \frac{1}{18} = \frac{3}{18} + \frac{2}{18} + \frac{1}{18}$

Step2: Sum numerators

$\frac{3+2+1}{18} = \frac{6}{18} = \frac{1}{3}$

(11)

Step1: Find common denominator (63)

$\frac{1}{7} + \frac{1}{9} + \frac{1}{21} = \frac{9}{63} + \frac{7}{63} + \frac{3}{63}$

Step2: Sum numerators

$\frac{9+7+3}{63} = \frac{19}{63}$

(12)

Step1: Find common denominator (80)

$\frac{1}{5} + \frac{1}{8} + \frac{1}{16} = \frac{16}{80} + \frac{10}{80} + \frac{5}{80}$

Step2: Sum numerators

$\frac{16+10+5}{80} = \frac{31}{80}$

Answer:

(7) $\frac{23}{28}$
(8) $\frac{11}{16}$
(9) $\frac{2}{3}$
(10) $\frac{1}{3}$
(11) $\frac{19}{63}$
(12) $\frac{31}{80}$