To convert a fraction to decimal, divide the numerator (top number) by the denominator (bottom number). For example: 3/4 = 3 ÷ 4 = 0.75. Some fractions produce repeating decimals (like 1/3 = 0.333...). To convert decimal to percentage, multiply by 100 (0.75 × 100 = 75%). These conversions are essential for math, cooking, construction, and everyday calculations.