# General Functionality

The GRE Quantitative section got more difficult and you'll need to learn when to use GRE calculator and when it is better to use your brain. At most on the test only one or two problems require the use of calculator, as mentioned, many can be done faster by estimating or identifying the "trick".

But before you start studying all the strategies and techniques you need to know few general things about GRE calculator.

## Order of operations

Due to its lack of functions, the GRE on-screen calculator looks a lot like a simple four-function calculator. However, this appearance is deceptive in one major aspect: **four-function calculators don’t obey the order of operations, but the GRE on-screen calculator does**. For example, to calculate (4+6)/5 in four-function Windows calculator, you could simply type:
and you’d get the right answer. On the GRE calculator, however, that sequence of keystrokes would produce the wrong result, since the fraction 6/5 would be computed before the 4 was added to the 6, **following PEMDAS order** (Parentheses, Exponents, Multiplication/Division, Addition/Subtraction). To perform the computation correctly on the GRE, you’d need to press the equals key an extra time:
or you can use the parentheses:
Both sequences would force the calculator to compute the sum 4+6 before dividing by 5. So, let's try to solve next problem using calculator:

## Parentheses

As mentioned above GRE calculator does have parentheses, however, they are coupled, meaning opened bracket should be closed before you could use it again. So, **you can't nest parentheses** such as 2×(4–(3+5)), you'll need to calculate the sum in brackets (3+5) separately and only then try to solve the above problem using calculator's parentheses.

## Sign and Square Root

Next functions you need to remember of are the Sign and the Square Root. The **Sign button** changes the sign of the currently displayed number. And using **the Square Root button** you will be able to compute the square roots. They both have the highest priority in order of operations. In next section you will have more practice on those two functions. Right now you can try this problem: