Convert 31 in base 10 to base 2?

To convert 31 in base 10 to base 2, you need to repeatedly divide the number by 2 and keep track of the remainders.

31 divided by 2 is 15 with a remainder of 1, so the rightmost digit in base 2 is 1.

15 divided by 2 is 7 with a remainder of 1, so the next digit in base 2 is also 1.

Continuing this process, you get 31 in base 10 is 11111 in base 2.