## Basic College Mathematics (10th Edition)

When subtracting two numbers, you need to regroup when: (a) the first (or top) number is a whole number or: (b) the fraction in the first (or top) number is smaller than the fraction in the second (or bottom) number Example of situation (a): $\displaystyle 10-5\frac{1}{3}=9\frac{3}{3}-5\frac{1}{3}=...$ Example of situation (b): $\displaystyle 10\frac{1}{3}-5\frac{2}{3}=9\frac{4}{3}-5\frac{2}{3}=...$