SEVEN PLUS TWO = EIGHTEEN MINUS NINE = EIGHTEEN OVER TWO
That’s true enough on its face. But Susan Thorpe discovered that if each letter is replaced with the number of its position in the alphabet (A=1, B=2, etc.), then the equivalence persists — the values in each of the three phrases total 191.
(Susan Thorpe, “Number Name Equations,” Word Ways 30:1 [February 1997], 34-36.)