The first number is how good it is, the second is how new it is. So an a42 would be the next step up in phones but still be quite old as it's a 2 in how new it is. 6 "newness" is the current number. The "how good it is" is usually 0-5.
So as goan said, the a36 would be the same kinda price and level of good but being a lot newer. The a56 is a lot newer and is 2 steps higher in how good it is
