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Solve a problem
EasyFractionsArithmetic

Compute 12+13\frac{1}{2} + \frac{1}{3}.

Fractions need a common denominator before adding.

Try it first: work the problem on paper, then open the solution below and compare each step.
Show the step-by-step solution

Final answer

56\frac{5}{6}

How we read your problem

Exact arithmetic with fractions (results kept in lowest terms).

Step-by-step solution

  1. Rewrite both fractions with the least common denominator

    The LCD of 2 and 3 is 6.

    12+13=36+26\frac{1}{2} + \frac{1}{3} = \frac{3}{6} + \frac{2}{6}
  2. Add the numerators and keep the denominator

    3+26=56\frac{3 + 2}{6} = \frac{5}{6}
  3. Final answer in lowest terms

    56\frac{5}{6}

Formulas used

  • Addition

    ab+cd=ad+bcbd\frac{a}{b} + \frac{c}{d} = \frac{ad + bc}{bd}
  • Multiplication

    ab×cd=acbd\frac{a}{b} \times \frac{c}{d} = \frac{ac}{bd}
  • Division

    ab÷cd=ab×dc\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c}

Fractions are combined over a common denominator for addition and subtraction, multiplied straight across, and divided by multiplying by the reciprocal. The result is reduced by the greatest common factor.

Verification

  • Decimal check: 5/6 ≈ 0.8333333333

About fractions

Simplify, add, subtract, multiply and divide fractions and mixed numbers.

Common denominator

To add or subtract fractions, rewrite them over a shared denominator, usually the least common multiple.

14+16=312+212=512\frac{1}{4} + \frac{1}{6} = \frac{3}{12} + \frac{2}{12} = \frac{5}{12}
Reciprocal

Dividing by a fraction is the same as multiplying by its reciprocal.

ab÷cd=ab⋅dc\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \cdot \frac{d}{c}

Check your own work