Fun With Maths-1

Fun with mathematics

Computing in a different way

Suppose we want to find the answer for 92 x 86, it can be done in a very simple way, though initially it may appear a bit lengthy.

Step I: Subtract 100 from both the numbers separately:

92 – 100 = -8 (i)
89 – 100 = -11 (ii)

Step II: Multiply the difference obtained as above:

-8 x –11 = 88 (iii)

Step III: Subtract the answer of equation (i) from second number or vice versa

89-8 = 81 (iv)
92-11 = 81 (v)

Step IV: The answer for the product 92 x 86 is obtained by putting result of equation (iv) or (v) at thousand’s and hundred’s places and equation (iii) at ten’s and one’s place, i.e. 8100 = 88 = 8188.

Let us take another example, i.e. product of 92 and 88. Going through the same steps as mentioned above, the results will be as given below:

Step I
92 – 100 = -8
87 – 100 = -13

Step II
-8 x –13 = 104

Step III
92 – 13 = 79
87 – 8 = 79

Step IV
In this case the result from step II has hndred’s place as well, this will be added to the result from step III, because the result of step III gives hundred’s place. So the answer will be: 7900 + 104 = 8004.

Let us take another example, where the numbers are grater than 100, ca 114 and 108. The same sequence of steps will be used in this case also.

Step I
114 – 100 = 14
108 – 100 = 8

Step II
14 x 8 = 112

Step III
114 + 8 = 122
108 + 14 = 122
(8 or 14 are added here because the algebraic sign of the numbers is plus)

Step IV
Add hundred’s place from step II to the answer from step III and the answer is: 12200 + 112 = 12312.

Let us take another example where one number is more than 100 and other is less than 100. Suppose the numbers are 119 and 92.

Step I
119 – 100 = 19
92 – 100 = -8

Step II
19 x –8 = -152

Step III
119 – 8 = 111
92 + 19 = 111
(19 is added here because the algebraic sign of 19 is plus and 8 is subtracted because the algebraic sign of 8 is minus)

Step IV
Add hundred’s place from step II to the answer from step III, ignore sign of step II and the answer is: 1110 – 152 = 10948 (subtraction carried out in this case because answer from step II is negative).

More interesting ways of computing will be shown in next article on Fun with Mathematics.

Where did One Dollar Go?

Three men went to a hotel and stayed there for a night. While checking out, the hotel accountant asked them to pay @ US $10 each and a total of US $30 all-inclusive. As soon as the three left the hotel, recollected that there was discount of US $ for a group booking of three persons. He immediately sent of his room boys to return them US $5. The room boy, while on the way, thought that it would be difficult to divide five dollars among three persons. So he kept two dollars with him and equally distributed three dollars among the three, giving one dollar to each of them. Now arises the problem of accounting.
Each of the three persons got one dollar back, so each one of them paid nine dollars. The room boy kept two dollars with him. That makes a total of US $ 29 (9*3 + 2 = 29). But they had actually paid a total of US $30. Where did the remaining One Dollar get lost in the process?

Answer in next article on Fun With Mathematics.