Yes, a human tells if a number is even by checking the last digit. But why does that work? Because we all (I think) learned some really nifty tricks when we were little:

• A number is divisible by 2 if it ends in an even digit (0, 2, 4, 6, or 8)
• A number is divisible by 3 if the sum of its digits is 3, 6, or 9 (and you keep summing the digits until you get to a one-digit number)
• A number is divisible by 4 if its last two digits are divisible by 4 (recursive, yes, but it takes a little extra brain power to determine if a two-digit number is divisible by 4)
• A number is divisible by 5 if its last digit is a 0 or a 5
• A number is divisible by 6 if it's divisible by 2 and 3
• and so on...

So there's a connection between the last digit of a number and its remainder modulo 2. That doesn't discount the fact that even-ness is determined via the remainder of the number modulo 2, it's just that the last digit modulo 2 is a shortcut.

$_="goto+F.print+chop;\n=yhpaj";F1:eval

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