Careless Mistakes Aren’t Your Fault, But You Must Do Something

In Study Hacks by Peter Peng4 Comments

At some point, we’ve all been a little brain dead. I once thought 10/5 was 5. Can you spot my flawed thought process here? (Hint: I subtracted, rather than divided).

But the girl in this video below really takes the cake. I guarantee it’ll be the funniest 5 minutes of your day. I was dyyyyiiing. You might want to sit down for this.

Now, I don’t really know if it was pure ignorance or a simple brain fart that caused her to fail so miserably, but the point is, we all have our dumb moments.

And that’s no laughing matter – we have to do something about these “careless” errors because they’re costing you anywhere in the neighborhood of 50-80+ points on the SAT or 3-5+ on the ACT.

Telling yourself “I knew that” or “I’ll be more careful” is the worst thing you can do here.

Brushing off your “careless” mistake without coming up with a solution is 1,000x dumber than your already dumb mistake.

I want to talk about the psychology of why we’re so prone to brushing off careless mistakes for a moment, but if you’re impatient, click here for the action steps you can take now to fix careless errors.

“I’ll be more careful” is the lazy man’s excuse. Think about it. Let’s say you just started to drive (woot woot for being 16!) and your mom tells you, “Be careful, sweetie!”

Uh huh. Of course you’re going to be careful. Who gets in a car with the intention of having an accident, right? They’re called accidents for a reason – you didn’t mean for them to happen. But that’s precisely why telling yourself to be careful doesn’t make you a single ounce more careful.

In fact, doing so can make you less careful because you become so focused on not committing the mistake that you end up making it anyway.

True story: it was a rainy day in Los Angeles several years back, and I was driving with totally bare tire treads (really dumb).

I knew I was playing with the safety gods, so I told myself, “Be extra careful and drive slowly.” I kept repeating this as I drove, as if chanting the words would magically save me. Ten minutes later, I hydroplaned straight into a concrete barrier, spun 180 degrees, and totaled my car.

That’s a bit dramatic, sure, but the effects of brushing off your “careless” mistakes are no less disastrous. Like I said, they are costing you nearly 100 points. That’s why I often tell my students you don’t need to learn more math to get a much higher score. You already know how to do it.

One time, I posed this question to a student: if you have 7 marbles, and 3/7th of them are red, then how many red marbles do you have?

Her answer? 10!

What…the…heck? How could she possibly have ended up with more red marbles than the total number of marbles she began with?

It’s quite simple actually. She saw 3/7th, so she added 3 + 7, which equaled 10. She didn’t stop to consider the stupidly simple logic that if you take a portion of a total, you will always end up with less than you began with.

The point of all this is twofold:

1) Don’t over-complicate things. Sometimes, the problem really is as easy as it seems. I often say the SAT is full of traps (and it is), but if you’re working on question #1, how hard is it really going to be? C’mon now. Look at the level of difficulty problem you’re working on. They generally get harder within each SAT math section.

2) Don’t just brush these “careless” mistakes off. I cannot emphasize this enough, and I’ll repeat it a million more times if that’s what it takes to help you.

We all know 7 x 5 is 35, not 30…and 8 + 6 = 14, not 13. And that the opposite of negative is not odd (it’s positive). But the solution is not “be more careful.” It’s impossible to just will yourself to be more careful. You have to put systems in place to catch yourself and prevent these errors from happening in the first place.

Allow me a moment to explain why it’s so easy to just brush things off. Why is it that our default response is to do the exact opposite of what we need to do to improve?

It’s because life has taught us that the conceptual part is the most important part. You’ve seen this in your math class – if you demonstrate your understanding of the theory behind the calculations by showing your work, you’ll get partial credit even if you end up with the wrong answer.

Not only that, but the conceptual part is the most rewarding part of the question. When it finally clicks, you feel a deep-earned satisfaction. If you make a calculation error, you feel it’s okay because you understand that.

But the SAT and ACT have no mercy. They don’t care if you actually don’t know any trig or geometry, or if you just forgot to switch your calculator from radian to degree mode or that you bungled 1 + 1. To them, you’re just flat out wrong.

Comprende? You got it wrong! Not a little wrong or somewhat wrong…ALL wrong. You cannot cut yourself any slack here.

It’s like being in the lead of a race and tripping at the finish line. You watch in horror as your opponents speed past you to finish a race you practically had in the bag.

And don’t think for a moment that you can go back and check your work, hoping to catch your error. You almost assuredly won’t. If you happen to think 10/5 = 5 in the moment like I did, you could stare at that step and go over it 3 more times and still think it’s fine. Your mind has already imprinted that flawed logic in your head, so it’s going to keep following through incorrectly. The error is glaringly obvious to everyone else, but you just can’t wrap your head around it at that moment.

Better to get it right the first time around. If you must double check, use a different method of solving the question. Otherwise, re-using your original method is going to cause your brain to follow the same flawed steps and arrive at the same flawed answer.

The stupider the error, the MORE worthy it is of your heavy consideration.

These are the EASY points, and if you’re not getting those, then what’s the point of getting the hard questions right?

In fact, the fact that these errors are so ridiculously silly and obvious is precisely why they’re so fatal. People like to think of themselves as above such mistakes. They think, “Oh yeah, I could have gotten that. It doesn’t count.”

It doesn’t count??! Just like how when you meant to bubble in D but you somehow bubbled C doesn’t count? Are you kidding me? Do you see why this is such a big problem?  Everything counts.

How to Fix Careless Errors (Action Steps):

1) Humble yourself and recognize you are not above your “careless” mistakes. I’m certainly not. I’ve had my share of embarrassing moments when I recognized the sheer stupidity spewing from my mouth. If your ego is in the way, you cannot possibly implement the following crucial tip.

2) Pretend you really are dumb. I’ve noticed that the smarter students are, the more dismissive they are of careless errors. This is the kiss of death. But if you pretend you are dumb, then you will write out every step, no matter how simple. You will stop doing mental math and skipping steps that you can normally conquer with no issue 99% of the time. You will punch in 50 x 20 in your calculator, just to be sure. You will carefully label units like feet, inches, etc.

The more basic steps you do, the less likely you will fall for careless mistakes. Stupid mistakes happen because your mind is focused on the higher level logic and feels it doesn’t need to pay too much attention to the simple stuff that you’ve normally can do in your sleep.

Humbling myself and subjecting myself to this embarrassingly rudimentary process is precisely how I went from 680-720 in math (despite understanding 100% of the questions) to an 800.

I had almost given up after three attempts. Every time, I thought I nailed it because all the questions were easy to me. And every time, I didn’t nail it…until I finally told myself to stop being an arrogant little guy. I implemented a system of writing out all the steps.

You have to ruthlessly attack these “careless” mistakes and put actual systems in place to stop them from happening. Think about WHY you made the careless mistake. “I don’t know; I just did” is totally unacceptable.

Really think about why. Was it because you subtracted rather than divided? Then what are you going to do about that? Perhaps you can write out the word “divide” next time you see that step. Whatever it takes. You just need to do something, an actual step (even if it’s tedious) beyond telling yourself you’ll do better next time.

Now it’s your turn. Comment below with a story of a time you made a careless mistake and what you plan to do now to banish it forever into the netherworld.


  1. Peter O'Leary

    So on the most recent SAT I took, there was a problem that told me there are a total of 24 cars, and there are half as many trucks as regular autos. It asked for the number of trucks. I thought to myself hmmmmm… This looks easy! 12! No more time wasted on this stupidly rudimentary problem that only someone with half a brain would miss! I looked over my test and nearly punched myself. I had half a brain at the moment of answering. (The answer, without a doubt, is 8). To fix this, I will read each problem, no matter how early on it is, sedulously. There is no reason I should get these ones wrong and rush to the harder ones. I will also underline the part that says “number if trucks” so that I know what I’m answering. Even writing this makes me cringe at my fatuousness! Never again shall I assume anything going into a problem except that I am stupid, and I will READ the problem that is given to me instead of feeling so darn superior!

    1. Author
      Peter Peng

      That’s awesome! If something is TOO easy, your spidey-sense should be tingling. Your mistake reminds me of this question this CEO asks potential employees he’s interviewing:

      A hammer and a nail cost $1.10 together, and the hammer costs one dollar more than the nail. How much does the nail cost?

      If you blurt out 10 cents, that might seem correct at first, but that would make the hammer cost $1.10 and make the total $1.20. Don’t assume things too fast. Can you come up with the correct answer here?

      You hit the nail right on the head (pun totally intended) about the need to stop feeling so darn superior. I find the smarter people are at math, the more often they fall for these sorts of silly mistakes. Dumb it down. Work through every step as if you’re truly dumb.

      One thing I suggest is bracketing and labeling your answer choices before you even read the whole problem. Just look at the last sentence where the question resides, then draw a big bracket around A, B, C, D, E and label it. For example, “total cost of eggs” or “3x” or whatever.

  2. Sonya K

    On May’s SAT, I got number two wrong on one of my math sections. I simply rushed through the question, assuming it was one of those easy questions…However, I mistook a negative number as a positive. The question asked about the sum of two points (-2 and -8) and I added 2 and 8, thinking -2 was positive 2. 🙁 *major SIGH* but now I know the importance of accurately reading the question. (:

    1. Author
      Peter Peng

      It’s great that you now know the importance of paying attention to negative signs. They are a HUGE killer.

      Same goes for square vs. square root. For example, what’s the square of 25? Most people say 5 because they are thinking the square ROOT of 25 is 5. But read carefully…the question asked what the SQUARE (alone) is. 25 x 25 = 625.

      There are so many possible careless errors like perimeter vs. area. Radius vs. diameter. Forgetting to double things if mentally split a figure in half. And much more.

      Sonya, I sent you an email the other day. Would love to hear what your biggest frustration or sticking point is.

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