Like most people who take the GRE, your Math knowledge might be a little rusty. The good news is that GRE only tests you on math that you have already learned in high school. If you are worried that you have forgotten most of what you learned in high school, you will...

Standard deviation is an important statistical term tested on the GRE. It gives you an insight into the deviation or dispersion of a set of numbers from its mean; therefore, a low standard deviation implies that the numbers are very close to the mean, and vice versa....

Every integer greater than 1 either is a prime number or a composite number. All composite numbers can be expressed as a product of prime numbers. For example, 6 can be expressed as 2 × 3. The prime factors of 6 are 2 and 3. Whereas the expression 2 × 3 is called...

Let's see how we use the chart to deal with this question: How many positive factors does 100 have? Set up the chart: 100 Left Column Right Column 1 100 2 50 4 25 5 20 10 10   Remember the rule - once the factors repeat themselves, (i.e. 10 and 10), stop. Since...

You've already seen the wonderful factor table - a simple technique for finding all the factors of an integer. Let's see how we use the chart to deal with this question: How many positive factors does 140 have? The question asks about factors, so the factor table is...

Some integer questions may require you to find the Factors of an integer. The factor table is a basic technique for finding all the factors of any integer. This technique can also be useful for questions asking how many factors a particular integer has. The technique...

Primes play a central part in integer questions. Overconfidence is dangerous here: while almost everybody can recite the definition of a prime number at the drop of a hat, the field is actually rife with misconceptions. We are here to make sure you know everything...

Let's formulate rules for addition, subtraction, multiplication, and division of Even and Odd numbers. Here are the rules for adding / subtracting even and odd numbers: Even ± Even = Even (e.g. 2 + 2 = 4; -4 - 2 = -6) Odd ± Odd = Even (e.g. 1 + 1 = 2; -31 - 1 = -32)...

We'll begin with the basic definitions: Even: any integer that is divisible by 2. Examples: 2, 4, 14. Odd: any integer that is not divisible by 2, i.e. leaves a remainder of 1 when divided by 2. Examples: 1, 3, 5, 7, 9 So far so good. Consider this potential...

Find the remainder when 5,142,376,298 is divided by 9?     The long division method will definitely tell you the remainder of dividing 5,142,376,298 by 9 but you can very well imagine how long would that take. The good news is that just like the divisibility...