# Calculate or Not to Calculate?

As you will soon realize, **ETS is not exactly looking out for your best interests**. Giving you a calculator might seem like an altruistic act, however there are only certain ways in which calculator use can be exploited in your favor. The test-makers will give you long, drawn out calculations and they'll want you to use the calculator in order to waste a precious time. Your best bet is to try and visually eliminate and only then calculate. **If you calculate every possible expression, we guarantee, you will run out of time.** Try these few problems:

Here below will be given few tips where you should or shouldn't use the on-screen calculator during your actual GRE.

# Don’t use GRE calculator only because it’s available!

Don’t use GRE calculator blindly, even though multiple digits are involved. You shouldn’t need the calculator to know that 25×300 = 7500, or that 130+135 = 265. As far as your brain is concerned, **the GRE on-screen calculator is a supplement — not a substitute**!

## Estimate/approximate whenever you can

**Sometimes it's much faster to get the answer through estimation:**

**Even if you're going to use GRE calculator you should also estimate.** In case you made a typo while punching the buttons, you could check the calculator’s answer against your estimated answer to make sure the answers are in the same neighborhood. And it's especially true with large quantities, a quick estimation can save you from those inevitable typos that come from punching long numbers into a calculator:

Besides, **often test-makers give us unpleasant numbers**, like 141,000 or 39%. However, in most cases we do not need calculator to perform all the tedious calculations, especially in those problems that use word "approximately" and the numbers in answer choices are sufficiently apart. Here's the problem you can try:

## Don't calculate: give it a glance and compare

In Quantitative Comparison problems **you don't always have to calculate the exact value of each quantity** before you compare them. After all, your mission is simply to compare the two quantities:

It's often helpful to **treat the two quantities as if they were two sides of an equation**. Almost everything you could do to the both sides of an equation, you can also do to both quantities: you can add/subtract the same number to/from both sides or you can multiply/divide both sides by the same positive number (not negative):

So remember: **do not start calculation immediately, always take a second or two to glance at each quantity**. You can follow this rule in other problem types as well: