Sunday, 27 July 2008

Solving Mental Math Questions through Simplification

Math questions can be solved mentally through many ways or methods.

(This is provided no specific method is spelled out in the math question itself).

Selection of the method to be used depends on our liking. If we found one method suitable for us, it will make the math solution easy and encouraging.

Different people has different preference.

Therefore choosing one method over another is not wrong.

There are 2 main approaches to solving mental math question.

- Solving directly which may be a faster way but care has to be taken as it may be complex and involves many variables and maths relation.

- Solving by simplification.

Let me cite an example (the focus of this post).

Example: Calculate MENTALLY 24 x 5

In mental math, multiplying using 5 is known to be more difficult than using 10.
We also know that 10 = 5 x 2, so let's use multiply by 10 first.

Step 1:
24 X 10 = 240.This is not the answer since it is x10, but since 5 = 10 / 2, we divide the 240 by 2.We again know that divide by 2 is also simple.

Step 2:
Divide the answer in step 1 by 2, 240 / 2 = 120(This is the final answer for 24 x 5)

What we have done is to use 2 simple numbers, that is 10 and later 2, to perform multiplication using 5 which may be mentally difficult to do.

We have converted a more difficult direct mental solving into 2 simple math steps that is less prone to error and fast.

The message here is we can choose to solve mental math questions using something that we are comfortable with by using the simplification method.

You see the nice part about choosing the right strategy?
You wouldn't get old mentally practicing mental maths!


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