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# Tip #22 to Get a Top ACT Math Score

By McGraw-Hill Professional
Updated on Sep 7, 2011

Many kids think matrices are super high-level math that they could never get, but the ACT asks only the most basic matrices questions. First, let's get the stress out. Have a good scream, hug it out, and we'll move on.

Mostly, the ACT uses matrices like ordinary charts, like the charts in Skill 15. Reading these is no different than checking the sports page. In fact, if these questions just omitted the word matrix, more kids would try them and get them right. Just including the word matrix in a question can change its ranking from "easy" to "hard."

There are a few things that the ACT might actually ask you to do with matrices.

• The first is to add matrices. This is so easy that you barely do it in school. To add matrices, you just add the numbers in each location. You'll see this in the drills.
• The second thing they could ask is for you to multiply matrices. They ask this very rarely, but the key when they do is to know that when you multiply two matrices, the result will have as many rows as the first and as many columns as the second matrix. For example, a 2-row by 3-column matrix times a 3-row by 4-column matrix will have 2 rows and 4 columns. And the middle numbers (3s in this case) must match or the matrices can't be multiplied.
• That's about it for big ol' scary matrices. If the ACT asks you to do anything else, they will tell you how to do it in the question. They won't expect you to have anything else memorized.

Let's look at this question:

Solution: This question definitely scares most kids away. But if we just drop the words matrix and matrices, it's a normal chart question. The first chart shows how many kids are in each club, and the second chart shows how the student body is divided by grades, i.e., the freshmen are 0.3 or "three-tenths" of the school. So 0.3 of the total of 20 kids in the Yoga Club must be frosh: (0.3)(20) = 6 freshmen in the Yoga Club.

Easy, right. Some kids think matrices belong in college-level Calc III, but on the ACT they are no problem!