# What is the least common denominator of 3/10 and 1/4?

LCD is $20$.
The denominators in $\frac{3}{10}$ and $\frac{1}{4}$ are $10$ and $4$.
Factors of $10$ are $2 \times 5$ and $2 \times 2$.
Hence LCD should have two 2's and one 5 i.e. $2 \times 2 \times 5 = 20$ and fractions can be written as $\frac{6}{20}$ and $\frac{5}{20}$.