Adding Fractions Worksheets with Answer Key - Free Printable

Let’s solve each fraction addition problem step by step. Remember: when adding fractions with unlike denominators, we need to find a common denominator first — usually the least common multiple (LCM) of the two denominators. Then convert each fraction, add the numerators, and simplify if needed.

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Problem 1:
$\frac{1}{4} + \frac{1}{2}$
→ LCM of 4 and 2 is 4.
→ $\frac{1}{2} = \frac{2}{4}$
→ $\frac{1}{4} + \frac{2}{4} = \frac{3}{4}$

Problem 2:
$\frac{3}{4} + \frac{3}{8}$
→ LCM of 4 and 8 is 8.
→ $\frac{3}{4} = \frac{6}{8}$
→ $\frac{6}{8} + \frac{3}{8} = \frac{9}{8} = 1\frac{1}{8}$

Problem 3:
$\frac{2}{4} + \frac{5}{6}$
→ Simplify $\frac{2}{4} = \frac{1}{2}$
→ LCM of 2 and 6 is 6.
→ $\frac{1}{2} = \frac{3}{6}$
→ $\frac{3}{6} + \frac{5}{6} = \frac{8}{6} = \frac{4}{3} = 1\frac{1}{3}$

Problem 4:
$\frac{3}{6} + \frac{1}{3}$
→ Simplify $\frac{3}{6} = \frac{1}{2}$
→ LCM of 2 and 3 is 6.
→ $\frac{1}{2} = \frac{3}{6}, \frac{1}{3} = \frac{2}{6}$
→ $\frac{3}{6} + \frac{2}{6} = \frac{5}{6}$

Problem 5:
$\frac{8}{3} + \frac{4}{5}$
→ LCM of 3 and 5 is 15.
→ $\frac{8}{3} = \frac{40}{15}, \frac{4}{5} = \frac{12}{15}$
→ $\frac{40}{15} + \frac{12}{15} = \frac{52}{15} = 3\frac{7}{15}$

Problem 6:
$\frac{2}{5} + \frac{5}{10}$
→ Simplify $\frac{5}{10} = \frac{1}{2}$
→ LCM of 5 and 2 is 10.
→ $\frac{2}{5} = \frac{4}{10}, \frac{1}{2} = \frac{5}{10}$
→ $\frac{4}{10} + \frac{5}{10} = \frac{9}{10}$

Problem 7:
$\frac{2}{3} + \frac{1}{2}$
→ LCM of 3 and 2 is 6.
→ $\frac{2}{3} = \frac{4}{6}, \frac{1}{2} = \frac{3}{6}$
→ $\frac{4}{6} + \frac{3}{6} = \frac{7}{6} = 1\frac{1}{6}$

Problem 8:
$\frac{4}{6} + \frac{5}{8}$
→ Simplify $\frac{4}{6} = \frac{2}{3}$
→ LCM of 3 and 8 is 24.
→ $\frac{2}{3} = \frac{16}{24}, \frac{5}{8} = \frac{15}{24}$
→ $\frac{16}{24} + \frac{15}{24} = \frac{31}{24} = 1\frac{7}{24}$

Problem 9:
$\frac{3}{9} + \frac{1}{3}$
→ Simplify $\frac{3}{9} = \frac{1}{3}$
→ $\frac{1}{3} + \frac{1}{3} = \frac{2}{3}$

Problem 10:
$\frac{6}{4} + \frac{5}{12}$
→ Simplify $\frac{6}{4} = \frac{3}{2}$
→ LCM of 2 and 12 is 12.
→ $\frac{3}{2} = \frac{18}{12}$
→ $\frac{18}{12} + \frac{5}{12} = \frac{23}{12} = 1\frac{11}{12}$

Problem 11:
$\frac{4}{6} + \frac{2}{9}$
→ Simplify $\frac{4}{6} = \frac{2}{3}$
→ LCM of 3 and 9 is 9.
→ $\frac{2}{3} = \frac{6}{9}$
→ $\frac{6}{9} + \frac{2}{9} = \frac{8}{9}$

Problem 12:
$\frac{9}{2} + \frac{2}{8}$
→ Simplify $\frac{2}{8} = \frac{1}{4}$
→ LCM of 2 and 4 is 4.
→ $\frac{9}{2} = \frac{18}{4}$
→ $\frac{18}{4} + \frac{1}{4} = \frac{19}{4} = 4\frac{3}{4}$

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Final Answer:
1. $\frac{3}{4}$
2. $1\frac{1}{8}$
3. $1\frac{1}{3}$
4. $\frac{5}{6}$
5. $3\frac{7}{15}$
6. $\frac{9}{10}$
7. $1\frac{1}{6}$
8. $1\frac{7}{24}$
9. $\frac{2}{3}$
10. $1\frac{11}{12}$
11. $\frac{8}{9}$
12. $4\frac{3}{4}$