Multiply 12.21 by 100: Decimal Number Calculation

To solve this problem, we'll follow these steps:

• Step 1: Identify the initial position of the decimal point in $12.21$, which is between the digits $2$ and $1$.
• Step 2: Shift the decimal point two places to the right. This movement changes $12.21$ to $1221$.
• Step 3: Confirm the resulting number, $1221$.

By multiplying $12.21$ by $100$, we shift the decimal point two spaces to the right, resulting in the number $1221$.