Multiplying by Fraction Close to 1

This trick involves clever factoring when multiplying a whole number by a fraction close to 1. By treating the fraction as $(1 \pm \text{small fraction})$, you can simplify the calculation.

For $14 \times \frac{15}{16}$, rewrite it as $14 \times (1 - \frac{1}{16}) = 14 - \frac{14}{16} = 13\frac{1}{8}$.

For $17 \times \frac{13}{11}$, rewrite it as $17 \times (1 + \frac{2}{11}) = 17 + \frac{34}{11} = 17 + 3\frac{1}{11} = 20\frac{1}{11}$. This avoids dealing with large improper fractions.