Question

efectuati 2+1/3
3+5/4
2 1/2+/3
5 1/4+1 1/2
3 1/3+1
2 1/7 +1 1/2
2 1/4 +3 1/3
5 1/2+2 1/7
1 1/20+2 1/12

Answer 1

A)
$2 + \frac{1}{3} = \frac{3 \times 2 + 1}{3} = \frac{7}{3}$

B)
$3 + \frac{5}{4} = \frac{4 \times 3 + 5}{4} = \frac{17}{4}$

C)
$2 \frac{1}{2} + \frac{1}{3} = \frac{2 \times 2 + 1}{2} + \frac{1}{3} =$
$= \frac{5}{2} + \frac{1}{3} = \frac{3 \times 5 + 2 \times 1}{6} = \frac{15 + 2}{6} = \frac{17}{6}$

D)
$5 \frac{1}{4} + 1 \frac{1}{2} = \frac{5 \times 4 + 1}{4} + \frac{1 \times 2 + 1}{2} =$
$= \frac{21}{4} + \frac{3}{2} = \frac{21 + 2 \times 3}{4} = \frac{21 + 6}{4} = \frac{27}{4}$
E)
$3 \frac{1}{3} + 1 = \frac{3 \times 3 + 1}{3} + 1 = \frac{10}{3} + 1$
$= \frac{10 + 3 \times 1}{3} = \frac{10 + 3}{3} = \frac{13}{3}$
F)
$2 \frac{1}{7} + 1 \frac{1}{2} = \frac{2 \times 7 + 1}{7} + \frac{1 \times 2 + 1}{2} =$
$= \frac{15}{7} + \frac{3}{2} = \frac{2 \times 15 + 7 \times 3}{14} = \frac{30 + 21}{14} =$
$= \frac{51}{14}$
G)
$2 \frac{1}{4} + 3 \frac{1}{3} = \frac{2 \times 4 + 1}{4} + \frac{3 \times 3 + 1}{3}$
$= \frac{9}{4} + \frac{10}{3} = \frac{3 \times 9 + 4 \times 10}{12}$
$= \frac{27 + 40}{12} = \frac{67}{12}$
H)
$5 \frac{1}{2} + 2 \frac{1}{7} = \frac{5 \times 2 + 1}{2} + \frac{2 \times 7 + 1}{7}$
$= \frac{11}{2} + \frac{15}{7} = \frac{7 \times 11 + 2 \times 15}{14} =$
$= \frac{77 + 30}{14} = \frac{107}{14}$
I)
$1 \frac{1}{20} + 2 \frac{1}{12} = \frac{1 \times 20 + 1}{20} + \frac{2 \times 12 + 1}{12}$
$= \frac{21}{20} + \frac{25}{12} = \frac{12 \times 21 + 20 \times 25}{240}$
$= \frac{315 + 500}{240} = \frac{815}{240} \div |5| = \frac{163}{48}$