## Articles by GMAT Prep Now

#### The GCD/LCM Formula

In the last two articles, we learned how to find the greatest common divisor (GCD) and the least common multiple (LCM). In this video, we examine a nice formula that shows the relationship between the GCD of and the LCM … Read More

#### Least Common Multiples on the GMAT

In this video, we examine two useful strategies for finding the least common multiple (LCM). We also practice finding pairs of numbers with a certain LCM. To help reinforce the concepts you learned in the video, try … Read More

#### Greatest Common Divisors (Factors) on the GMAT

In this video, we examine two different strategies for finding the greatest common divisor. We also practice finding pairs of numbers that have a certain greatest common divisor. To help reinforce the concepts you … Read More

#### Squares of Integers on the GMAT

Many integer properties questions on the GMAT involve the squares of integers, which are sometimes called “perfect squares.” In this video, we examine some important properties of the “perfect” squares. To help … Read More

#### Prime Numbers on the GMAT

The GMAT tests your knowledge of prime numbers in many different ways. In this two-video article, we’ll examine some important properties of prime numbers. To begin, let’s make sure you fully understand what prime … Read More

#### Solving Mixture Questions on the GMAT

Learn a useful strategy for solving a wide range of mixture questions on the GMAT. Once you’ve watched the video, use the technique to answer the following practice questions: Practice question #1 Practice question #2 Read More

#### Variables in the Answer Choices—Part III: Tips for the Input-Output Approach

In the last two articles (click here to see Part I and Part II), we examined two strategies for answering questions with variables in the answer choices: Algebraic approach Input-output approach In this video, we examine … Read More

#### Variables in the Answer Choices—Part II: Tips for the Algebraic Approach

In the last article, we examined two popular strategies for answering questions with variables in the answer choices: Algebraic approach Input-output approach In this video, we examine some useful tips to consider when … Read More

#### Variables in the Answer Choices—Part I

Most Problem Solving questions on the GMAT have numbers for the answer choices. This, however, isn’t always the case. A common question type on the GMAT features variables in the answer choices, and these questions … Read More

#### 3-Criteria Overlapping Sets on the GMAT

In this video, we examine how to solve questions involving populations in which each member of that population has three criteria associated with it. Once you’ve watched the lesson, try answering the following … Read More

#### Sums of Sequences (a.k.a. Series) on the GMAT

Some GMAT questions ask us to find the sums of sequences. In this video lesson, we’ll examine two important concepts you need to know to answer these questions. Once you’ve watched the video lesson, try answering … Read More

#### Recursive Sequences on the GMAT

GMAT questions involving recursive sequences are often difficult. In fact, some students have trouble getting past the strange notation. In this video, we examine the notation used to define recursive sequences and how … Read More

#### Introduction to Sequences on the GMAT

When it comes to sequence questions on the GMAT, many students like to apply formulas they learned in high school. The problem with this is that, when sequence questions are posed in nonstandard formats, these formulas … Read More

#### GMAT Motion Questions with Multiple Trips and/or Multiple Travelers

In this video, we learn how to solve advanced motion questions in which we have multiple trips and/or multiple travelers. Read More