1 + 2 = 3
1 + 4 = 3
16 + 4 = 11
4 + 4 = 7
5 + 4 = 6
5 + 2 = 10
6 + 2 = 10
2 + 2 = 7
8 + 10 = 5
4 + 10 = 4
5 + 10 = 4
3 + 10 = 5
81 + 7 = ?


Hint

$10 + 1 \ne 1 + 10$

Hint 2

The number four

What is the pattern? What is 81 + 7? How are the results calculated?

• Question is 2+2 actually equal to 7? – Going hamateur Oct 14 '16 at 18:26
• I suggest using a non mathematical symbol instead of + to make this puzzle less confusing. Maybe @? 1 @ 2 = 3, 1 @ 4 = 3, etc. – MMAdams Oct 14 '16 at 18:26
• @MMAdams Possibly, but I did make it pretty clear – Okx Oct 14 '16 at 18:28
• @Goinghamateur Maybe :) – Okx Oct 14 '16 at 18:28

81+7= 11
81's base 7 representation is 144. Which is onefourfour, which is 11 letters long.
81-49 = 32 (1) ->3
32-28 = 4 (4) ->4
4 = 4 (4) - > 4
3+4+4 = 11

Explanation:

take the first number, put it in the base of the second number, and count the number of letters in the representation.

How I got it:

The ? + 10 = ? numbers gave it away for me. 8 is 5 letters, 4 is 4 letters, 5 is 4 letters, 3 is 5 letters.