Solve the Fraction Subtraction: 3/7 minus 1/6

List the multiples of each number: 7: 7, 14, 21, 28, 35, 42... and 6: 6, 12, 18, 24, 30, 36, 42... The first number that appears in both lists is 42, so that's your LCD!

Because fractions represent parts of different wholes! $\frac{3}{7}$ means 3 parts out of 7, while $\frac{1}{6}$ means 1 part out of 6. You need the same-sized pieces (same denominator) to subtract.

Any common multiple will work, but using the LCD (42) keeps your numbers smaller and easier to work with. If you use 84, you'd get $\frac{36}{84} - \frac{14}{84} = \frac{22}{84}$, which simplifies to the same answer!

Check if the numerator and denominator share any common factors. Since 11 is prime and doesn't divide into 42, $\frac{11}{42}$ is already in simplest form.

Double-check your multiplication: $\frac{3}{7} \times \frac{6}{6} = \frac{18}{42}$ and $\frac{1}{6} \times \frac{7}{7} = \frac{7}{42}$. The key is multiplying by equivalent forms of 1!