The problem asks to find a number such that $40\%$ of that number is equal to $40$. The equation is: $40\% \times x = 40$, where $x$ is the missing number.

1. Problem Description

The problem asks to find a number such that $40\%$ of that number is equal to $40$. The equation is: $40\% \times x = 40$, where $x$ is the missing number.

2. Solution Steps

First, we can write $40\%$ as a decimal: $40\% = \frac{40}{100} = 0.4$.

Then the equation becomes: $0.4 \times x = 40$.

To find $x$, we divide both sides of the equation by $0.4$:

$x = \frac{40}{0.4}$.

To make the division easier, we can multiply both the numerator and the denominator by $10$:

$x = \frac{40 \times 10}{0.4 \times 10} = \frac{400}{4}$.

Finally, we perform the division:

$x = \frac{400}{4} = 100$.

3. Final Answer

100