Solve: 2/3 - 1/15 - 2/5 | Triple Fraction Subtraction

List the multiples of each number: 3: 3, 6, 9, 12, 15... 15: 15, 30, 45... 5: 5, 10, 15, 20... The smallest number that appears in all lists is 15.

Sometimes the biggest denominator is the LCD (like 15 here), but not always! For example, with denominators 6 and 8, the LCD is 24, not 8. Always check that your chosen number is divisible by all denominators.

Yes, always simplify! $\frac{3}{15}$ looks messy, but $\frac{1}{5}$ is much cleaner. Divide both numerator and denominator by their greatest common factor (3 in this case).

Lucky you! Like $\frac{1}{15}$ in this problem - it stays exactly the same. You only need to convert fractions that don't already have the LCD as their denominator.

You could, but it's much harder! You'd need to find LCD twice: first for $\frac{2}{3} - \frac{1}{15}$, then again for that result minus $\frac{2}{5}$. Finding the LCD of all three at once is more efficient.

Substitute your answer back: $\frac{2}{3} - \frac{1}{15} - \frac{2}{5}$ should equal $\frac{1}{5}$. Convert everything to fifteenths: $\frac{10}{15} - \frac{1}{15} - \frac{6}{15} = \frac{3}{15} = \frac{1}{5}$ ✓