### Brain Teasers

# Not Six

Group
These brain teasers rely on your ability to recognize groups of common attributes. For each of these puzzles you'll need to figure out why the words or letters are grouped as they are. Sometimes you will be asked to pick the odd-one-out or to place a new word into the correct group.Group

A: 1,2,3,4,5,7,8,9,10,11,13,14,15,16,17,19

B: 12,18,20

What are the groups and why is the number 6 not included?

B: 12,18,20

What are the groups and why is the number 6 not included?

### Hint

It has nothing to do with even or odd, but all primes are in the same group### Answer

All numbers in group A are greater than the sum of all numbers they are divisible by (except for themselves). I.e, 1+2+5<10. In group B, all numbers are less than the sum of all numbers they are divisible by (except for themselves). I.e, 1+2+3+4+6>12. The number 6 is omitted because all numbers it is divisible by add up to 6. 1+2+3=6Hide Hint Show Hint Hide Answer Show Answer

## What Next?

View a Similar Brain Teaser...

If you become a registered user you can vote on this brain teaser, keep track of which ones you have seen, and even make your own.

### Solve a Puzzle

## Comments

Nice one. It was kind of hard.

ooah whadya mean"B"

That totally didn't make sense to me I had way easier answers!

ok that was really hard for me

This numerical trait of six is also known as being a "perfect number." There are others, in high school I wrote a computer program that found perfect numbers.

Admittedly, I'm a wordsmith, not a math whiz; nevertheless, that one was the first that made me feel like a complete retard. Even after reading the answer.

this was pretty wow

Pretty witty, good job!

6, 28, 496 would be omitted.

To post a comment, please create an account and sign in.

## Follow Braingle!