To convert a hexadecimal number to a decimal number, you can use the following steps:

1. Write down the hexadecimal number.
2. Assign each hexadecimal digit to its corresponding decimal value (0-9, A-F).
3. Multiply each digit by 16 raised to the power of its place value, starting from the rightmost digit.
4. Add up all the products from step 3.

Here’s an example:

Convert the hexadecimal number 3D to decimal.

1. Write down the hexadecimal number: 3D
2. Assign each hexadecimal digit to its corresponding decimal value:
   • 3 = 3
   • D = 13
3. Multiply each digit by 16 raised to the power of its place value:
   • 3 * 16^1 = 48
   • 13 * 16^0 = 13
4. Add up all the products from step 3:
   • 48 + 13 = 61

Therefore, the hexadecimal number 3D is equal to the decimal number 61.