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5 tips to avoid careless mistakes | Math Lobby

Updated: Nov 26, 2022

Everyone makes careless mistakes. But top students who excel in Math know how to double check their work to avoid careless mistakes.

At Math Lobby, we see a lot of students making careless mistakes because they are anxious to go through each question to get the answers and just want to complete all the questions in the Math exam.

These types of careless mistakes can be exceedingly costly. It can be between an A grade and a B grade, a passing mark and a failing mark.

In this post, we will be covering why we make careless mistakes, the types of careless mistakes and how we can avoid them.

Why we make careless mistakes:

Careless mistakes occur because of the following reasons:

1.Mind is not focused at the task at hand/ Split attention

Students might miss information, miscopy a number or forget to include a negative sign from line to line in their working. This could be because their mind might be focused at recalling the formulas or doing other questions.

2. Complacency

Students might see the same questions appearing to what they have practiced and become over-confident,complacent and over-efficient. The task becomes routine and habitual and the student no longer needs to think about what they may be doing. This increases the chance of making careless mistakes.

3. Foundation skills are not fully developed/ Lack of mastery

Some students need more work with the fundamental concept and more application. These types of careless mistakes occur when the concepts are not understood thoroughly. They have not consolidated their understanding to the point where they can consistently apply what they know.

Another point to this is that students understand the concept but fail to perform the computation accurately due to lack of understanding of the question.

The types of careless mistakes students make can be classified as follows:

1. Units error

Units error occurs when you overlook units in the question or did not express the units correctly in the answers.

For example, the question below states that

a) A train travels 160 km at an average speed of 96 km/h. How long does this

journey takes in mins?

Students who are often careless ignore the fact that the answer requires them to express the journey taken in minutes..

2. Conceptual error

Conceptual error occurs when you are not sure of the fundamental concept or the possible meaning behind the words in the question.

This could be due to not having met the word before due to not practiced enough.

There could be a possible conceptual error in this question:

Paula bought an antique chest at a discount of 20%. If she received a discount of $98, calculate

a) its marked price,

b) its selling price.

The marked price of something is 100%.

In this case, the marked price is

20% - $98

100% - $490

Some students might mistake the marked price as the price after the discount. Which in this case is not correct.

3. Calculation error

Calculation error is when you make mistakes in your working or mis-typing a number in your calculator.

There are 36 men, 24 women and 52 children in a swimming pool.

a) Find the ratio of the number of children to the total number of people.

a) Children : Total no. of people

= 52 : (36 + 24 + 52)

= 52 : 106

= 26 : 53

Instead of keying in 36 in (36 + 24 + 52), students might misread and key in 30 in the calculator, resulting in a calculation error.

4. Transfer error

Transfer error is error when you fail to transfer the right number from the question to the working or from the working to the answer.

For example, you are required to solve x in the in the equation below:

2x + (x + 29) = 152

Instead of rewriting +29, you have written an extra 0 resulting in +290. This results in a wrong answer.


3x + 290 = 152

3x = -138

x =-46


3x + 29 = 152

3x = 123

x = 41

5. Presentation error

Presentation errors are errors which you make in the final answer. For example, forgetting to write the answer in 3 decimal places or the right significant figures.

There could be a possible presentation error in this question:

A rectangular wooden board measures 11.14 m by 8.06 m.

a) Find the area of the board, giving your answer correct to 3 significant figures.

11.14 x 8.06 = 89.7883

≈ 89.79 instead of 89.8

Some students leave their answers in 2 decimal places instead of 3 sf which the question asks for.

How can we avoid careless mistakes:

These are the ways where we can avoid careless mistakes:

1. Units error

Check the units in the final answer with the question.

2. Conceptual error

Check your understanding and logic of the question

3. Calculation error

Check your workings with the calculator again

4. Transfer error

Check if you forget to include the minus sign or a number

5. Presentation error

Check if you have presented the answers in standard notion, the right significant figures (SF) or decimal place.

Lastly, don't forget to leave time to double check your work! Remember, the Math exam paper is not a race, but a slow jog. It does not matter if you have completed early but it is essential to get most of the questions correct and leave no marks on the table.

If you have any pending questions, please do go on to our Facebook page, Instagram or contact us directly at Math Lobby! We have certified mathematics tutors to aid you in your child’s journey to become a better student!

As always: Work hard, stay motivated and we wish all students a successful and enjoyable journey with Math Lobby!

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