Did you pay attention in school?

[Vinny]

You have the D and M switched from what I learned. We learned the last 4 stood for "My Dumb Ass Sister". Either way, M & D carry the same weight, as do A & S, so both ways are correct.

I came up with the same thing as Greg until I was reminded that subtraction is actually addition of negative numbers. Here's how Quora explains it:

2-2*2+1

Separate each number with corresponding sign

(2)+(-2)*(2)+(1)

then

(2)+(-2*2)+(1)

=>(2)+(-4)+(1)

=>(2)+(-4+1)

=>2+(-3)

=>2–3

=>-1

Even tho -3 makes more sense!