The hexadecimal number `FFFF` can be converted to decimal as follows:
- \( F \) in hexadecimal is \( 15 \) in decimal.
- The place values from right to left are \( 16^0, 16^1, 16^2, \) and \( 16^3 \).
Calculating it:
\[
FFFF = F \times 16^3 + F \times 16^2 + F \times 16^1 + F \times 16^0
\]
\[
= 15 \times 4096 + 15 \times 256 + 15 \times 16 + 15 \times 1
\]
\[
= 61440 + 3840 + 240 + 15
\]
\[
= 65535
\]
So, the decimal equivalent of `FFFF` is **65535**.