# A glass that holds 0.5 liters (L) will hold how many milliliters (mL)?

$500$ $m L$
The prefix $\text{milli}$ $\equiv$ ${10}^{-} 3$.
Thus $1$ $m L$ $=$ ${10}^{-} 3 L$.
$0.5 \cancel{L} \times \frac{m L}{{10}^{-} 3 \cancel{L}}$ $=$ $500 \cdot m L$