The ACT Math Formula You Need To Know

When it comes to the ACT Math test, the biggest challenge you’ll face is time management. You’ll have sixty minutes to answer sixty questions – all without any formulas provided to you. 

You’ll have to memorize all the formulas for the test beforehand and ensure you know them well enough to apply them when needed. Abstract concepts can be challenging to teach and learn, so you may want to look towards other mediums to learn.

To help, we’ve compiled a list of some crucial formulas you’ll want to remember.


There are two main sections to focus on in algebra: linear equations and functions and logarithms.

Starting with linear equations and functions, you’ll want to memorize the formula for calculating a slope, a slope-intercept form, and the midpoint formula.


The slope measures how a line changes according to the x- and y-axis. It’s relatively simple to calculate: measure the change and the y-axis/the change along the x-axis, more commonly represented as the rise over/divided by the run. 

So with two points on a graph (point A and point B) and their coordinates ((x1,y1) and (x2,y2)), you would use the following formula:

(y2−y1) / (x2−x1)

Slope Intercept Form

For the slope-intercept form, you’ll want to use the linear equation y = mx + b, where m is the slope and b is the y-intercept. A line that passes through the origin is written as y = mx. Be sure to always work with this basic formula, as it will tend to be easier and quicker to understand, so rewrite equations into this formula as required.


To calculate the midpoint of two points on a graph (A and B), you can use the following formula to calculate the x-axis and y-axis points, respectively:


(x1+x2) / 2


(y1+y2) / 2

For the most part, you’ll just have to rewrite logarithms, such as the following for example:

logbx = y= >by = x


logbxy = logbx + logby

Statistics and Probability

There are a few things to keep in mind when looking at statistics and probability, two of which we’ll go over.


First of all is averages, which means you’ll want to find either the standard of a set of numbers (or terms) or the average speed of something. For the former, you’ll want to calculate the mean by dividing the sum of the terms of numbers by the number of different terms in total. Speed is equal to distance divided by time.


Probability is calculated by dividing the number of desired outcomes by the total number of possible outcomes. You can then calculate the probability of two independent outcomes both happening in a set of tests by multiplying the probability of both outcomes together.

Concluding Thoughts

There are many different formulas to remember and memorize, with this being a brief crash course that only scratches the surface. For more in-depth information, you can find more formulas here. Math can be enjoyable if you get to grips with the motions of its formula.

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