Archive for the ‘Mental Maths’ Category
Tuesday, November 20th, 2007
With flexibility in the arrangement of numbers to be multiplied, mental multiplication can be easily done with numbers that seems to be big.
Example: 21 can be splitted into 20 + 1 = (2 x 10) + 1
With this splitting of "big" number, 21 becomes operations using only 2, 10 and ...
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Wednesday, November 14th, 2007
In maths, while doing division of numbers, sometimes we arrived at fraction, be it improper or proper form. We may need to have the answer in decimal.
Mentally how do we get the answer fast and simple?
To have this fast conversion from fraction to decimal, we first need to memorise some ...
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Thursday, November 8th, 2007
What is meant by "close-by" numbers?
Example: 22 and 25, 34 and 38, numbers that differs by a few ones away.
Mental multiplication of these number can be performed with a special technique.
The trick is to use the Special product in quadratic equation,
(a + b) ( a - b) = a2 - ...
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Friday, November 2nd, 2007
Mental math calculation does not only involve the four basic operations of addition, subtraction, division and multiplication. There are times where we need to perform special but common manipulation, like logarithm or indices.
Example: 10x = 8
To solve this example, we need to convert it into the logarithm form to move ...
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Thursday, November 1st, 2007
In mental division, there is an Inflation Method (named by me) that magnifies the number to get an easy number to manipulate mentally.
Another sister method of Inflation method is the so-called Deflation Method.
In this Deflation method of Mental Maths division, we need to scale down to a "better" number. Examples ...
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Thursday, November 1st, 2007
There are many methods to do mental math division. One method is presented here.
I call it the Inflation method.
The concept is to multiply the number (denominator) to a "better" or simpler number to operate. Examples of "better" number are 10, 20 , or 100 .
Let's do an example.
34 / 5 = ?
5 when multiplied ...
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