Board Thread:Local Games/@comment-24323080-20150215004520/@comment-25104452-20150222170524

221. 9 + 10 = 21. THIS IS TRUE!!!

Factor out 9 and 10, you get 3*3 and 5*2.

Now, multiply 3*2 and 5*3 and you get 6 and 15.

Now add them together, you get 21!