Three Tips for Using a Calculator on SAT and ACT

When we show students how to leverage their graphing calculators for success on the SAT and ACT, they often reply, "Wow – I never knew I could do that!"

But which calculators are allowed on the SAT and ACT? The short answer is that anything without a QWERTY keypad is allowed on the SAT, and anything less than a TI-89 is allowed on the ACT. (For more info, consult the Calculator Policy for SAT and ACT.)

Having tutored thousands of students for both tests, we find the TI-84 Plus CE is the sweet spot: not too fancy, often required for high school math classes anyway, and containing all the functionality you'll need for either math section. Whether your high school curriculum utilizes calculators all the time or once in a blue moon, there are a few essential features every SAT and ACT test-taker needs to know.

1. FRAC

Oftentimes, the SAT or ACT will give simplified, algebra-derived fractions in the answer set. In these cases, the most efficient path to the correct answer is through decimal calculations. Facility converting between decimal numbers and their fractional equivalents is crucial not only to avoiding tedious algebra, but also to eliminating unrealistic answers. We place the Frac technique at the top of the list primarily because we use it so frequently!

Here's how to use this feature:

• Locate the number you need to convert to a fraction and bring it to the home screen.

• Key MATH > NUM > Frac. The decimal answer will be converted to the most reduced form of the fraction. (If the decimal number reappears unchanged, this means that the number is irrational, or unable to be represented as a fraction.)

2. GRAPHING

Likely the most underused feature of SAT and ACT students' calculators! We regularly tutor students whose attempts to manually draw and graph functions in the coordinate plane suck up precious time and are not drawn to scale – jeopardizing the accuracy of their answers.

Here are the most common scenarios where utilizing the graphing functionality of your calculator is an effective problem-solving method:

• Solving a system of equations: Y= > [input] > 2ND > CALC > Intersect.

• Finding the critical points of a parabola: Y= > [input] > 2ND > CALC > zero (or minimum or maximum).

• Extrapolating a function or equation with a table of values: GRAPH > [input] > 2ND > TABLE. (Pro Tip: To calibrate x-values, hit 2ND > TBLSET and edit the ∆Tbl entry.)

Both tests also typically present visual answer choices (e.g., "Which of the following represents the graph of the given function in the coordinate plane?"). With a calculator, it’s as easy as graphing and selecting the answer that matches your screen!

3. APPS

Most graphing calculators come equipped with a suite of applications (found via the purple APPS button on a TI-84) with basic tutorials on conic sections (APPS > CONICS), number sense and linear algebra (APPS > ALG1PRT1), and area formulas for obscure polygons (APPS > AreaForm). A lesser-known app is Inequalz, designed to graph inequalities in the coordinate plane. (ACT usually has at least one problem on this topic.)

In addition to these stock applications, many more helpful apps and programs can be found on the internet. Just plug your trusty USB cord into your computer, download these helpful resources, and transform your handheld into a SAT or ACT Math lightsaber.

Contact us today to learn more concrete tips from an expert SAT or ACT tutor!