I read this very early in the morning and it took me a long while to figure out what the joke was. I was trying to see something in "on a roof" and "fell"... but then the actual joke hit me.Two aerials met on a roof, fell in love and got married. The wedding was crap, but the reception was brilliant.
12 + 144 + 20 + 3√4 + (5 x 11) = 9² + 0
Waddya mean you don't get it? It's clearly:
A dozen a gross and a score
plus three times the square root of four
Divided by seven
plus five times eleven
is nine squared and not a bit more.