Question

What is a GEMDAS rule?

Answer 1

it's pretty much PEMDAS buuttt if you don't know that
G= grouping
E=powers and roots
M=Multiply
D=divide
A= add
S= subtract

Answer 2

@shei.caguitla

It has to do with the order of operations when simplifying algebraic or arithmetical expressions. In some texts, it is known as PEMDAS, BODMAS, or BEDMAS. Read more about it and the order of operations at the given link.

"... when you see something like ...

7 + (6 × 52 + 3)

... what part should you calculate first?

Start at the left and go to the right?
Or go from right to left?

Warning: Calculate them in the wrong order, and you will get a wrong answer ! "

http://www.mathsisfun.com/operation-order-pemdas.html