Do I need a common denominator to multiply?
No — only for addition and subtraction. Multiplication and division work straight across, which is why they are usually the easier operations.
Perform fraction arithmetic with automatic simplification. Add, subtract, multiply, or divide fractions and mixed numbers.
a/b + c/d = (ad + cb) ÷ bd. a/b × c/d = ac ÷ bd. a/b ÷ c/d = ad ÷ bc. Simplify by dividing both parts by their GCD.
3/4 + 2/5 = (15 + 8)/20 = 23/20 = 1 3/20. Multiplying instead: 3/4 × 2/5 = 6/20, which simplifies to 3/10.
No — only for addition and subtraction. Multiplication and division work straight across, which is why they are usually the easier operations.
Multiply by the reciprocal: flip the second fraction and multiply. 1/2 ÷ 3/4 becomes 1/2 × 4/3 = 4/6 = 2/3.
Divide the numerator by the denominator. 5/8 = 0.625. Denominators with prime factors other than 2 and 5 produce repeating decimals, like 1/3 = 0.333…