Convert the binary number 1111 to decimal.

Convert the binary number 1111 to decimal.

• A. 12
• B. 13
• C. 15
• D. 14

Answer: (C)

Binary to decimal conversion is about adding the powers of two for every bit that is 1. For a four-bit number, the rightmost bit is 2^0, the next is 2^1, then 2^2, and 2^3. If all four bits are 1, you add 2^0 + 2^1 + 2^2 + 2^3, which equals 1 + 2 + 4 + 8 = 15. So 1111 in binary equals 15 in decimal. The other possible totals would come from turning some of the 1s to 0, which reduces the sum, so they would be smaller values.

Binary to decimal conversion is about adding the powers of two for every bit that is 1. For a four-bit number, the rightmost bit is 2^0, the next is 2^1, then 2^2, and 2^3. If all four bits are 1, you add 2^0 + 2^1 + 2^2 + 2^3, which equals 1 + 2 + 4 + 8 = 15. So 1111 in binary equals 15 in decimal. The other possible totals would come from turning some of the 1s to 0, which reduces the sum, so they would be smaller values.