I've always known that as 'I ate all the pies' but either way, it was the pie that's delicious
√-1 = i (i is an imaginary number such that i²=-1)
2³ = 8 Hopefully this doesn't need explaining
Σ = Mathematical symbol for the sum of a set of numbers
π = Pi, a mathematical constant which is used so, so much - mainly for circle geometry but it also comes into trigonometry as well.
√-1 2³ Σ π = i 8 sum pi