This is the third part in a series of how to conquer SAT and ACT Math by utilizing a Math Toolbox. For the complete list of the tools in the Math Toolbox and Part 1, visit here. Now that you mastered how to best use your pencil and your calculator, it is time to learn how to use the math tools you don’t carry in your pocket on test day. The first of said tools is mental math.
I mentioned mental math in the last post by stating that a calculator is not needed for every calculation since many problems can be solved in your head. The truth is, if you have to pull out your calculator for every problem on the SAT calculator math section or the entire ACT math section, you will waste a lot of time. Instead of using the calculator as a crutch, learn to leverage your mental math. Mental math isn’t really that hard. Say you have to multiply 408 by 12. Sounds like a problem that requires a calculator, right? Actually, it doesn’t. 408 x 12 is the same as (400 x 12) + (8 x 12). With mental math, you break calculations down into manageable chunks. 4 x 12 is 48, so 400 x 12 is 4800. 8 x 12 is 96 so your final answer is a pretty easy sum of 4800 + 96 or 4,896. Another useful trick with mental math is estimating. Often on the SAT and ACT, you can eliminate answer choices and get closer to the correct answer quickly by estimating. For example, let’s say there is a question asking the area of an L-shaped pool. You could calculate the area of one section of the pool then add that to the calculation of the area of the other section. This would mean two different calculations which means lots of time. On the other hand, with mental math, you could estimate the area of both sections pretty quickly and eliminate any answer choices that are too small or too large. In most situations, this means you would eliminate as many as three answer choices. Now, with the hard work already done, you can back into the correct answer much faster by looking at the remaining answer choices. But more on the back door in a future blog post as that is another tool in your math toolbox. Ultimately, mental math can take you far when it comes to saving time and uncovering correct answers. Calculators are a useful tool but they can slow you down. Let your brain do some heavy lifting and watch correct answers appear faster. Next post will address the next math tool: translating. For more test-taking tips, contact CROSSWALK and learn how we prepare students stress-free for the SAT, ACT, PSAT, SSAT and more.