Fractions and Decimals
Adding/subtracting fractions: Find a common denominator, then add/subtract numerators.
Multiplying fractions: Multiply numerators together, multiply denominators together, then simplify.
Dividing fractions: Multiply by the reciprocal of the divisor — "flip and multiply."
Mixed number → improper fraction: 3½ = (3 × 2 + 1)/2 = 7/2
Comparing fractions: Cross-multiply. For 3/4 vs 5/7: compare 3×7=21 to 4×5=20. Since 21 > 20, 3/4 > 5/7.
Decimal ↔ fraction: 0.75 = 75/100 = 3/4. To convert a fraction to a decimal, divide numerator by denominator.