Section: Mathematics

10) If a number is expressed in binary, which of the following is a necessary and sufficient condition to test whether it is divisible by 2?

1. If the number does not end in 0.
2. If the alternating sum of the digits is 0 or divisible by 3.
3. If the number includes an even number of 1's and an even number of 0's
4. If the number, when converted to decimal form, has the sum of its digits divisible by 3.

If a binary expression ends with a 1 then the number is not divisible by 2.