Magoosh’s experts provide you with all the GMAT math prep you need to start your quantitative reasoning practice before test day.

Consider the following geometry Data-Sufficiency Questions.  All are related to the diagram below: 1) Is quadrilateral ABCD a square? (1) AB = CD (2) A = 90º (A) Statement 1 alone is sufficient but statement 2 alone is not sufficient to answer the question asked.   (B) Statement 2 alone is sufficient but statement 1 […]

Recently, in a GMAT forum, someone asked: “I am facing this problem with plugging numbers on the DS section. I realized this happens when I miss plugging in some specific numbers that just turn around the answer of the question. When I plug in, say, 2, the statement is sufficient, but plug in -1/2 and […]

GMAT Math will ask you about absolute values.  Mastering the GMAT algebra skills to answer them requires sophisticated understanding. Somewhere along the line, perhaps in middle school, you probably learned:   |positive| = positive and |negative| = positive   In other words, the equation |x| = 5 has the solution: x = 5 or x […]

Here are five quick tips to make you much more effective at interpreting and solving GMAT problems involving percents, one of the most common GMAT questions.   Percents and Decimals Fundamentally, a percent is a fraction out of 100 – it is per centum (Latin for “per 100”).  It’s easy to change a percent to […]

Dice problems aren’t too common on the GMAT. As for the exact probability of getting a dice problem is something only privy to those over at GMAC. While it is a good idea to know your dice basics, doing so will only help you in the case of an easy dice problem. And one thing […]

There’s an old saying that says, “Almost only counts in horseshoes and hand grenades.”  In grade school and high school, you were probably taught that math had to be precise; maybe you even had that unforgivingly drilled into you.  Well, now you’re preparing for the GMAT, and the rules are different.  On GMAT Math, “almost” […]

The GMAT will ask you about geometric solids. The OG tells you that you should expect questions about rectangular solids and cylinders. Here, I will discuss four less common solids that are much less likely to appear on the GMAT Math section: the prism, the pyramid, the cone, and the sphere. For all of these, […]

According to the GMAT OG, there are two 3D solids you should understand in detail are (a) rectangular solids, and (b) cylinders. On any given GMAT, you will see no more than a couple questions on 3D solids, but they definitely could appear, especially if you are already getting many questions right and are moving […]

A Case Study of the Area of an Equilateral Triangle Fact: on the GMAT Math section, you are likely to find questions about the area of an equilateral triangle, and it would be efficient if you knew the formula.  (BTW, the formula appears a little further below.)   Don’t Merely Memorize I am going to […]

Permutations A permutation is a possible order in which to put a set of objects.  Suppose I had a shelf of 5 different books, and I wanted to know: in how many different orders can I put these 5 books?  Another way to say that is: 5 books have how many different permutations? In order […]

Formulas A rate is how fast something is growing, changing, or being performed.  The overarching rate formula is: Amount = Rate x Time   When the rate is a speed, this simplifies to the familiar formula: Distance = Speed x Time   In questions about speed, especially where an object travels at one speed for […]

Everyone knows how to find an average, but the power of this formula is often underestimated.  We know: average = (sum of the items)/(number of items) Notice, we can also write this as: sum of items = (average)*(number of items) This latter form can be powerful.  For example, if we add or subtract one item […]

As you may remember from high school, , where b is the base and h is the height.  If you are having trouble remembering this, simply remember that a rectangle has an area of , and that a triangle is half a rectangle. Practice Question: Using the Area Formula The figure on the left is […]