Excuse my question, but how do you read these numbers. Are they hexadecimal or like binary code?

The numbers that are currently being sieved are 2,1031- and 5,389-. This is a common notation for the numbers 2^1031 - 1 (i.e., 2 to the 1031 power minus 1) and 5^389 - 1.

Of course, whenever possible, we take out algebraic factors. For example, our next number, 2,979+ (or 2^979 + 1) is divisible by 2^89 + 1 leaving the long but useful
2^890 - 2^801 + 2^712 - 2^623 + 2^534 - 2^445 + 2^356 - 2^267 + 2^178 - 2^89 + 1
It is this latter, smaller number we will actually be factoring. For brevity, though, we still refer to this as 2,979+.