The episode was called "Mathlete's Feat". There was a math joke of the day (an equation) with the punch line "and it was delicious". What did the math equation say?

It said √-1 2^3 ∑ π which means "I ate some pie ... and it was delicious!"

Because √-1= i

2^3=8 (eight=[ate])

∑ = sum (which sounds like "some")

π=pi=3,1415....