If you are beginning your preparation for the GRE Quantitative Section, you might start with the Arithmetic chapter in your prep materials. (I recommend the Manhattan 5 lb GRE Practice Problems.)
Keep in mind, though, that the makers of the GRE can and do create spaghetti out of the most basic arithmetic. Why do they do this? I will explain more in another post, but there are some reasons we can infer right off. They are not testing whether you can do arithmetic—it is a given for achieving a credible score—but rather, how well you can reason quantitatively using arithmetic. And arithmetic is only the beginning.
Here is an example:
On a certain planet, they have sold 2.3 billion lottery tickets. 1 in 50 million are winners. How many winners are there? (The online calculator allowed on the exam handles up to 8 digits only.)
(A) 5
(B) 4.6
(C) 46
(D) 460
(E) 4600
Solution:
Alternatively, you could use scientific notation. But, you cannot brute force the large numbers into the calculator. Many of my new students rely heavily on the calculator, but not for long (heh heh).
This problem is testing your facility with place value, and your attention to detail. It may seem basic, but many candidates need to review.
Some people will be able to do this problem mentally, but be careful—it’s easy to lose a decimal place or two.