To solve the question "5 is 5% of what number?", we can set up an equation. Let's denote the unknown number as \( x \).
The equation can be expressed as:
\[ 5 = 0.05 \times x \]
Now, to solve for \( x \), we can rearrange the equation:
\[ x = \frac{5}{0.05} \]
Now, we can perform the calculation:
\[ x = \frac{5}{0.05} = 5 \div 0.05 = 5 \times 20 = 100 \]
Therefore, the unknown number is
\[ \boxed{100} \]
To verify, we check if 5 is indeed 5% of 100:
\[ 5% \text{ of } 100 = 0.05 \times 100 = 5 \]
This confirms that the solution is correct. The number is \( \boxed{100} \).