Maths Common Mistakes 3

Dear all,

Here is the continuation of the maths common mistakes.

Topic: FRACTIONS

Fractions stresses on the importance of identifying the correct NUMERATOR AND DENOMINATOR. The definition of fraction refers to parts out of a whole.

In the fraction



3 is the numerator while 4 is the denominator. DENOMINATOR refers to the total number of parts of a whole while NUMERATOR refers to the number of given parts.

Pupils need to be able to identify the correct numerator and denominator of a fraction.

In this equation of adding fractions,



The most common mistake to simply add up both the numerators and denominators to get a final answer of 3/8 (3 out of 8). THIS IS WRONG.

WE ADD UP THE NUMERATOR! but we DO NOT add up the denominator! THIS IS AN IMPORTANT RULE FOR fractions. Be it adding or subtraction, we do not add up the denominator.

The most important rule when we compare fractions or add and subtract fractions is to LOOK at the DENOMINATOR FIRST! Ask yourself

"Are the denominators the same? If they are not the same, how do I change them into the same denominator?"

- USE either the lowest common multiple method or
- you can multiply both their denominators together



Remember that if both the numerators and denominators are the same number, like 2/2 or 8/8, the fraction makes one whole.

Now, take a look at this question.

"Tom cut his cake into 9 slices. His mother are 2/3 of the cake. How many slices are left?"

COMMON MISTAKE: Pupil will leave the answer as a fraction. (1/3)

The correct answer should be 3 slices. remember, if you see the words slices or pieces, the answer should be a whole number and not a fraction.