Board Thread:Anything Goes/@comment-26335978-20170412011701/@comment-30979292-20170430130244

10 + 9 = n

10 = 5x2

9 = 3x3

SWITCH!

5x3 + 2x3

15 + 6

21

n = 21.

Which is better, me explaining 10+9=21 or me explaining 10+9=19?