A little riddle: When does Φ + V = 5?
Φ, the Greek symbol for phi, represents the number 1.61803398874989…, which is intrinsically related through math and geometry to the number 5.
V is the Roman symbol which represents the number 5.
So when does 
All you mathematicians are probably rushing to your calculators, knowing that the answer must be when V = 5 – Φ, or 3.38196601125011…
But this is a riddle, not an equation.
The answer is: “When you express it phonetically rather than mathematically.”
Just say “phi” and add the “v” sound to get “phive,” or five!
Curious that these numbers should all be related phonetically and mathematically, isn’t it?