Understanding Fractions
A fraction represents a part of a whole, written as one number over another separated by a line. The top number (numerator) represents how many parts you have, while the bottom number (denominator) represents how many equal parts make up the whole.
Types of Fractions
Proper Fractions
The numerator is smaller than the denominator, representing a value less than 1. Examples: 1/2, 3/4, 5/8.
Improper Fractions
The numerator is equal to or larger than the denominator, representing a value of 1 or more. Examples: 5/4, 7/3, 9/9.
Mixed Numbers
A combination of a whole number and a proper fraction. Examples: 1 1/2, 2 3/4, 5 1/8. This calculator accepts mixed numbers and can convert between formats.
Fraction Operations
Adding Fractions
To add fractions with the same denominator, add the numerators and keep the denominator. For different denominators, first find a common denominator.
Same denominator: 1/4 + 2/4 = 3/4 Different: 1/3 + 1/4 = 4/12 + 3/12 = 7/12
Subtracting Fractions
Similar to addition—find a common denominator if needed, then subtract numerators.
3/4 − 1/4 = 2/4 = 1/2 1/2 − 1/3 = 3/6 − 2/6 = 1/6
Multiplying Fractions
Multiply numerators together and denominators together. No common denominator needed.
2/3 × 3/4 = (2×3)/(3×4) = 6/12 = 1/2
Dividing Fractions
Multiply by the reciprocal (flip the second fraction). "Keep, Change, Flip"
2/3 ÷ 4/5 = 2/3 × 5/4 = 10/12 = 5/6
Finding Common Denominators
The Least Common Denominator (LCD) is the smallest number that both denominators divide into evenly. To find it:
- List multiples of each denominator
- Find the smallest number that appears in both lists
- Or calculate: LCD = (d1 × d2) / GCD(d1, d2)
Simplifying Fractions
To simplify (reduce) a fraction to its lowest terms:
- Find the Greatest Common Divisor (GCD) of numerator and denominator
- Divide both by the GCD
12/18: GCD(12,18) = 6 12÷6 / 18÷6 = 2/3
Converting Between Formats
Mixed to Improper
Multiply whole number by denominator, add numerator, keep denominator.
2 3/4 = (2×4 + 3)/4 = 11/4
Improper to Mixed
Divide numerator by denominator. Quotient is whole, remainder is numerator.
11/4 = 11÷4 = 2 remainder 3 = 2 3/4
Fraction to Decimal
Divide numerator by denominator.
3/4 = 3 ÷ 4 = 0.75 1/3 = 1 ÷ 3 = 0.333...