5
$\begingroup$

Since my previous cute, easy number puzzle turned out to be a duplicate, I felt I needed to redeem myself.

$2+9 = 6$
$7+8 = 8$
$9+6 = 5$
$0+9 = 6$
$1+4 = 6$
$9+9 = 3$
$2+6 = 6$
$6+4 = 7$
$1+5 = 6$

@TroyAndAbed:
$12+27 = 8$

What does:
$5+5 = ?$
Why?

Hopefully isn't too hard, please ask if you need any test cases.

HINT 1

Use the title of the question

Improve this question
$\endgroup$
7
  • 2
    $\begingroup$ I hope it isn't 10 ;-p $\endgroup$
    – Mark N
    Jul 16, 2015 at 18:19
  • 1
    $\begingroup$ If 5+5 isn't 10 I am in trouble for my upcoming 2nd grade math test... $\endgroup$
    – Going hamateur
    Jul 16, 2015 at 18:24
  • $\begingroup$ Any chance this uses equivalence classes? $\endgroup$
    – Going hamateur
    Jul 16, 2015 at 18:38
  • 1
    $\begingroup$ Is 12 + 27 possible or does it works only with number < 10? $\endgroup$
    – TroyAndAbed
    Jul 16, 2015 at 18:43
  • $\begingroup$ @Goinghamateur It doesn't involve equivalence classes. $\endgroup$
    – qwertylpc
    Jul 16, 2015 at 19:11

1 Answer 1

Reset to default
4
$\begingroup$

How many total letters are used at least once in the spellings of the words
So 5+5= 4

That is a strong hint

Improve this answer
$\endgroup$
3
  • $\begingroup$ Ya, I couldn't think of a more moderate hint $\endgroup$
    – qwertylpc
    Jul 16, 2015 at 19:17
  • $\begingroup$ Also I was nervous because of all my down votes :( $\endgroup$
    – qwertylpc
    Jul 16, 2015 at 19:17
  • $\begingroup$ Yeah with pure mathematical questions to get upvotes you need to weave it into a story it seems, feels more organic too. $\endgroup$
    – Going hamateur
    Jul 16, 2015 at 19:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.