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Arithmetic drills

Fraction calculation practice

Fraction arithmetic rests on three skills: common denominators, cancelling and reciprocals.

Math problem generator

Level

Reducing and common denominators

To reduce a fraction, divide the numerator and denominator by a common factor, ideally the greatest one: 1824=34\frac{18}{24} = \frac{3}{4}.

To add or subtract fractions with different denominators, rewrite them with a common denominator, usually the least common multiple.

56+34=1012+912=1912\frac{5}{6} + \frac{3}{4} = \frac{10}{12} + \frac{9}{12} = \frac{19}{12}
Tip

Always check whether your answer can be reduced.

Multiplying and dividing

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

Dividing by a fraction is the same as multiplying by its reciprocal. Cancel common factors before multiplying to keep the numbers small.

Example: 65÷97=65×79=1415\frac{6}{5} \div \frac{9}{7} = \frac{6}{5} \times \frac{7}{9} = \frac{14}{15}

Mixed numbers and decimals

Convert mixed numbers to improper fractions first: 213=732\frac{1}{3} = \frac{7}{3}.

When decimals and fractions appear together, convert the decimals to fractions (0.75=340.75 = \frac{3}{4}, 1.2=651.2 = \frac{6}{5}).

The order of operations is the same as with whole numbers:

34+23×38=34+14=1\frac{3}{4} + \frac{2}{3} \times \frac{3}{8} = \frac{3}{4} + \frac{1}{4} = 1