# Non-Negative integers in to three groups

The non-negative integers are divided into three groups as follows:

A = {0,3,6,8,9...}, B = {1,4,7,11,14...}, c={2,5,10,13...}

Explain ? I have no idea how to proceed.

• I am sorry, but those aren't groups. They are sets. Groups must have an associative binary operation, an identity, and inverses for each element. Commented Oct 19, 2014 at 22:14
• @Quincunx Your statement is precisely correct, but I think it's pretty clear that he's using the term group in an informal sense. Commented Oct 20, 2014 at 1:21
• @WChargin Unfortunately, I get really bugged when I see improper (informal) language... Commented Oct 20, 2014 at 18:15
• @Quincunx Maybe it's formal language in a discipline other than yours. Or perhaps it's a literal translation of formal terminology in the OP's native language. In any case, I think perfectly precise terms wouldn't add anything useful to this question.
– Muqo
Commented Oct 21, 2014 at 12:35

## 1 Answer

A contains integers (typically) composed of just curved lines when written. B contains integers (typically) composed of just straight lines when written. And C contains integers (typically) composed of both curved and straight lines.

kaine has pointed out that "12" seems to be missing. If you do a web search for the following, you can see that kaine is likely correct: "0, 3, 6, 8, 9" "1, 4, 7, 11, 14", "2, 5, 10, 12, 13"

• Nice one, didn't see this coming Commented Oct 20, 2014 at 12:27
• So 12 is missing from c? Commented Oct 20, 2014 at 18:31