Quick Six Times (I)

By now you might have understood that we can increase our efficiency in calculations by observing number behavior and linking many observations together with each other.

We are going to use many things we have learned so far to find out six times of any number quickly.

A very simple way to find out six times of any number is to write that number six times and then add! But it is going to take lot of time. Hence, we use a multiplication table of six times! However, if we try to find out a more mechanical way of finding out six times, we need not have to waste our time in recalling the six times multiplication table.

For doing six times quickly we can follow a two step method: Step I: Find five times of the number. Step II: Add the number itself to the product obtained in Step I.

Suppose we want to find out six times of 6482.

The conventional method of using the table of six and the multiplication using the two steps method above are presented below: .

We have obtained same answer using both the methods. You may think that, the first method appears shorter than the second one! Yes it is indeed! However, the second method can be made into one step and more mechanical too! Find out five times of the number by using the trick presented in the article Quick Five Times . This is surely easy and fast!

You can see that first we have added one zero to the right of the number 6482. Then we have divided each number by 2 mentally and written down the quotient of each division. Through this procedure we have managed "5 times of 6482."

If we make the addition of 6482 to "5 times of 6482" as well more mechanical we will have a method, which enables faster calculation. Still better way will be combining the two calculations, i.e. adding the number while we find out "5 times of that number." Let us see if we can devise such a method. For this we will inspect the addition of the number to "five times of that number". .

From the arrangement of the two addends, which are 32410 and 6482, we can easily find out a rule simplifying the complete calculation. The rule is "to each number add half of the right-hand neighbor". There are two exceptions to this rule when we calculate six times, as the first digit and last digit of any number will have no neighbors. In the case of these two digits we do the following. Since, the digit in the 'Ones' place has no right-hand neighbor, we write it as it is. In the given example, we write '2' as it is. Whereas, the digit to the extreme left, which is 6, has no digit to its left. Hence, we write simply 'half' of it, which is 3, as it is. Thus, no addition is required for the first and the last digit in the given number.

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