Avoid These Careless SAT and ACT Math Mistakes

Even the best students make math mistakes. The SAT and ACT math tests can be difficult, intimidating, and tricky. However, most students don’t need to be able to answer the hardest problems in order to get an average or above-average score. What they should be able to do, though, is answer the easy, medium, and upper-medium questions flawlessly–without making any of the following careless errors.

I often tell my students that if they know how to solve a problem and get the wrong answer as a result of a careless error, they’re robbing themselves of a point they deserve. There’s no shame in not knowing how to do a problem; you can simply learn the concepts unfamiliar to you and learn how to do the problem and do problems like it. But making a careless mistake on a problem you KNOW how to solve–well, there’s nothing more frustrating than that. The following is a list of careless SAT and ACT math mistakes.

Forgetting to balance the equation during algebra

Algebra’s actually a pretty free exercise: you can do pretty much anything you want, but whatever you do, you’ve got to do to both sides of the equation! If you multiply one side by three, don’t forget to multiply the other side by three!

Thinking that 1 is a prime number

It’s not a prime number.

Making mistakes with “tricky” exponents

If you don’t know how to handle an exponent to a negative power, a fractional power, or a negative fractional power, maybe it’s time to brush up on your exponent rules!

Forgetting to multiply by 100 when working with a percent

If you’ve got a decimal and want a percent, you’ve got to multiply by 100. This seems obvious, but during the middle of a long and complicated problem or algebraic calculation, don’t let yourself forget it!

Adding percentages instead of multiplying them

If Jane increased her mile time by 10% one year and then by 20% the next year, her mile time is 32% of what it was–not 30%. “Of” means multiply, not add.

Forgetting that problems with absolute value or squares will have TWO solutions

There’s both a positive AND a negative solution for absolute value and squared questions

Wasting too much time on one problem

Nothing’s worse than spending all your time on a difficult problem only to run out of time for later problems.

Not noticing a special right triangle

You should be able to recognize 30-60-90 and 45-45-90 triangles and know where they commonly hide! Not only that, you should know the ratios! Don’t just rely on the formula chart–that’s another waste of time.

Forgetting what an integer is

An integer is a whole number, positive, negative, or zero.

Rushing through easy questions to get to hard questions

There’s no point in getting a difficult question correct if you missed three easy questions on your way there.

Not using enough parentheses in your calculator

Don’t let your calculator rob you of a point. Make sure you use enough parentheses in your calculator for it to properly perform the operations you want it to perform.

Forgetting to flip an inequality sign when dividing by a negative number

This one’s self-explanatory.

Trusting a picture marked “not drawn to scale”

Trust nothing!


Bubble the correct answer in the correct place.

Solving for x instead of y

Remember to double-check what the question’s asking for.

Forgetting to convert

Don’t get them inches when they want miles.

Misplacing a decimal

Don’t accidentally write decimal point in the wrong place. It messes up your work by a lot!

Forgetting a negative sign

Do not forget to keep track of each and every negative sign in your work. Making mistakes with negative signs is the number one careless SAT and ACT math mistake!

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That’s it! For more SAT and ACT prep tips, as well as college readiness articles, read the rest of our blog. Looking for 1-on-1 college counseling or SAT or ACT group classes or tutoring? Contact us today!


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