10101 to decimal with method

To convert the binary number 10101 to decimal, you can use the method of expanding the number into powers of 2 and adding them together.

Starting from the right, each digit in the binary number represents a power of 2. So, in the binary number 10101, the digits from right to left represent the powers of 2 as follows:

1 * 2^0 = 1
0 * 2^1 = 0
1 * 2^2 = 4
0 * 2^3 = 0
1 * 2^4 = 16

Now, add all these values together:
1 + 0 + 4 + 0 + 16 = 21

Therefore, the binary number 10101 is equal to the decimal number 21.