Add, subtract, multiply, and divide fractions
Fractions represent parts of a whole and are fundamental to mathematics, cooking, construction, and many everyday activities. Understanding fraction operations helps you work with recipes, measurements, and proportional relationships.
A fraction consists of two parts: the numerator (top number) shows how many parts you have, and the denominator (bottom number) shows how many parts make up the whole. For example, in 3/4, you have 3 out of 4 equal parts.
To add or subtract fractions, you need a common denominator. Find the least common multiple of the denominators, convert both fractions, then add or subtract the numerators.
Multiply fractions by multiplying the numerators together and the denominators together. This is often easier than addition/subtraction because no common denominator is needed.
To divide fractions, multiply by the reciprocal (flip) of the second fraction. So a/b ÷ c/d becomes a/b × d/c.
a/b + c/d = (ad + bc)/(bd)
Find common denominator: LCM(b,d), then add numerators
a/b - c/d = (ad - bc)/(bd)
Find common denominator: LCM(b,d), then subtract numerators
a/b × c/d = (a×c)/(b×d)
Multiply numerators and denominators directly
a/b ÷ c/d = a/b × d/c = (a×d)/(b×c)
Multiply by the reciprocal of the second fraction
a/b = (a÷GCD)/(b÷GCD)
Divide both numerator and denominator by their Greatest Common Divisor
W r/s = (W×s + r)/s
Where W is whole number, r/s is the fraction part
Decimal = numerator ÷ denominator
Example: 3/4 = 3 ÷ 4 = 0.75