Fraction
A part of a whole written as numerator over denominator.
- Equivalent fractions reduce to the same value.
- Add via common denominator.
- Multiply numerators and denominators directly.
When to use: MSE normalizers (1/n), learning-rate fractions, probability ratios.
Example: MSE = (1/n) · Σ(y − ŷ)². The 1/n averages the squared errors.