How to Avoid Silly Mistakes on Tests

Students often lose easy marks on tests because of “silly” mistakes. Things like:

• Dropping a negative sign in the middle of a calculation
• Writing 3*2 = 5 or 3+3=9 (arithmetic mistakes)
• Answering a different question than what was asked (misreading the question)

As math problems get longer and more complex, these mistakes can be easier to make.

Many students think silly mistakes are out of their control and can’t be avoided. Like, “I knew the material, I just made some silly mistakes”.

However, silly mistakes lower your test scores just like any other kind of mistake, and in fact, they can be fixed.

Here are some strategies to avoid them.

Read the Question (Slowly and Carefully)

The importance of this cannot be overstated.

Observe what information is given, and what is unknown.

Figure out what the question is asking for (what should be your final answer).

Underline key information, particularly numbers (so it’s easier to refer to later).

It’s easier to know what techniques you need to solve the problem when you know what the goal (the final answer) should be.

After you’re done answering the question, re-read the question again to make sure you provided the kind of answer the question is looking for.

Students often immediately start solving the problem without carefully looking at the details, and end up not answering the question properly, and so they lose marks or get stuck.

Use Only One Technique Per Step (Write it Down)

Write more steps and work, rather than less.

The less you try to do mentally, the less likely you are to miss something.

Students often try to do multiple steps in their head in one line, which leads to mistakes.

If you’re solving a long equation or doing a lot of algebra, only change one thing each time. The other unchanged parts should look identical from one line to the next.

For combining like terms, underline what you’re combining so you don’t miss a term by accident.

Write as neatly and organized as you can. For example, align equal signs vertically.

This helps you read your own handwriting (many students have made mistakes because they misread their own writing), and it helps the grader clearly see your correct work.

This also makes double-checking your work easier, because you can just follow your steps one-by-one.

Don’t be Ashamed to Use Your Calculator

Feel free to use your calculator for even “simple” operations, like adding fractions or multiplying numbers.

Many students feel embarrassed about doing this, because they think it looks lazy or unsophisticated.

However, in a timed test, mental math often leads to small and unnoticed mistakes that can trickle down to a wrong final answer, that can derail your entire solution.

Also, math is not primarily about calculation. Using a calculator frees your mental focus for the harder reasoning parts of the question.

Using your calculator (and having a powerful calculator) reduces the chance of arithmetic mistakes, as long as you learn to use it. See my Calculator Guide for Students.

Practice to Maximize Familiarity

Study until you achieve mastery of the material, until you can consistently and dependably get questions correct.

Students often say “I knew the material, but I didn’t have enough time to finish”. This makes the poor performance seem like it’s out of your control.

However, a test is naturally a rushed environment, because it is designed to test not only your knowledge of the material, but also if you can demonstrate it under time pressure.

You know this ahead of time. The more familiar you are with the material, the faster you can complete the questions (correctly), and so the less likely you will run out of time.

Also, the more likely you will have extra time to double-check your work, to catch any silly mistakes.

Double-check your work at the end of the test.

End-of-test checklist:

Is my final answer precisely what the question is asking for?

• e.g. The question says “find the radius,” but you gave the diameter.
• e.g. You found x, but the question asked for the dimensions of the rectangle.
• e.g. The problem asked for “the equation of the line,” and you gave just the slope.

Did I include units in my final answer? (For word problems)

• e.g. You found time = 2, but didn’t say 2 seconds or 2 hours.
• e.g. You found cost = 12, but didn’t put $.
• e.g. You found the area = 25, but didn’t write cm².

Did I box my final answer?

• This just helps the grader clearly see your final answer quickly, and helps you quickly double-check that you actually wrote it down.