To find the missing number, we can set up the equation based on the information provided:
\[ 52 \times x = 520 \]
To solve for \( x \), divide both sides of the equation by 52:
\[ x = \frac{520}{52} \]
Now, calculate the right-hand side:
\[ x = 10 \]
Thus, the missing number is \( 10 \).