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Maths and your Mobile No

Subodh ( ) (402 Points)

10 September 2008

Here is a math trick so unbelievable that it will stump you.

Personally I would like to know who came up with this. It is Pretty Amazing.

1. Grab a calculator.

2. Key in the first six digits of your mobile number ( India mobile No only)

3. Multiply by 80

4. Add 1

5. Multiply by 250

6. Add the last 4 digits of your phone number (Not the total of 4 digits.)

7. Add the last 4 digits of your phone number again. (Not the total of 4 digits.)

8. Subtract 250

9. Divide number by 2

Do you recognize the answer?

Thanking you in anticipation.

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18 Replies

(Guest)

Hello

Good

Have you any technique in which if we have know first 6 digits,not last 4 digits then how we can know that ?

Please reply

Gaurish (Chartered Accountant) (46 Points)
Replied 10 September 2008

good one..

Rushikesh (Chartered Accountant - Manager Finance) (2375 Points)
Replied 10 September 2008

Amazing!!!!!

CMA Lakshminarayana Pulipaka (Practicing Cost Accountant) (118 Points)
Replied 10 September 2008

Hi Subodh,

Its really miracle. a great calculation. keep it up.

arpita (c.a. final student) (188 Points)
Replied 10 September 2008

great subodh...it works.....!!!!

Rangarajan (CA Student) (200 Points)
Replied 10 September 2008

Hey that’s a cool trick u got there.

Do anyone know the basis of such a trick.

It is very simple. It is law of Association.

I will illustrate it.

Take for instance this. Pick a number, add 2, multiply by 4, subtract 8, divide by 4. You get the number you started with

Take any number. Say X

Add 2 to it, v get X + 2. Multiply by 4. v get (X+2)*4. the result is 4X+8. now subtract 8. v get 4X. then divide by 4. v get X.

What happens is that, in the above example v perform 2 actions first and the rest 2 actions are performed to nullify the effect of the first 2 actions. First v add 2 and then multiply by 4. It is same as multiply the original number by 4 and adding 8. At the end v subtract 8 to cancel the effect.

The same can be noted with the above mention cell number trick.

The steps can be easily understood

1. Take first 6 numbers of any cell number

2. Multiply with 80

3. Add 1 to it

4. Multiply with 250

5. Add the last 4 digits of ur number

6. Again add the last 4 digits ur number

7. Subtract 250

8. Divide by two

The answer is always ur cell number.

Here, law of association begins in the step 3 and ends in step 7. Say the result of step 2 is X. performing step 3, v get X+1. Performing step 4, v get (X+1)*250, that is (X*250+250). Assuming “y” is to be the last 4 digits. Performing step 5 and 6, v get (x*250+250+2y). now performing step 7, v get (x*250+2y). It is like the step 3 and 7 are nullifying each other.

So, v can safely remove both, step 3 and 7. So v get

1. Take first 6 numbers of any cell number

2. Multiply with 80

3. Multiply with 250

4. Add the last 4 digits of ur number

5. Again add the last 4 digits ur number

6. Divide by two

The result will still be the same.

Now combine step 1 and 2, instead of multiplying with 80 and then by 250, v can directly multiply by 20000.

The net effect is that the six digit number is multiplied by 2 and then moved to the right by 4 digits.

Now v add twice the last 4 digits. Why twice the last 4 digits? It can be only once also, if the 6 digits are multiplied with a net effect of 10000. But it is not so. It is multiplied by twice of 10000. This twice is again removed altogether in step 6.

That is u can safely remove the last step 6. U will get

1. Take first 6 numbers of any cell number

2. Multiply with 10000

3. Add the last 4 digits of ur number

In these three steps, whatever 10 digit number u take, u get the same number. This is the basis of the trick.

It is one of the oldest trick in the oldest book.

Regards

Rangarajan.K

Aspirant (Audit Assistant) (56 Points)
Replied 10 September 2008

Originally posted by :Rangarajan
"	good information rangarajan. keep it up. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions / table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Hey that’s a cool trick u got there. Do anyone know the basis of such a trick. It is very simple. It is law of Association. I will illustrate it. Take for instance this. Pick a number, add 2, multiply by 4, subtract 8, divide by 4. You get the number you started with Take any number. Say X Add 2 to it, v get X + 2. Multiply by 4. v get (X+2)4. the result is 4X+8. now subtract 8. v get 4X. then divide by 4. v get X. What happens is that, in the above example v perform 2 actions first and the rest 2 actions are performed to nullify the effect of the first 2 actions. First v add 2 and then multiply by 4. It is same as multiply the original number by 4 and adding 8. At the end v subtract 8 to cancel the effect. The same can be noted with the above mention cell number trick. The steps can be easily understood 1. Take first 6 numbers of any cell number 2. Multiply with 80 3. Add 1 to it 4. Multiply with 250 5. Add the last 4 digits of ur number 6. Again add the last 4 digits ur number 7. Subtract 250 8. Divide by two The answer is always ur cell number. Here, law of association begins in the step 3 and ends in step 7. Say the result of step 2 is X. performing step 3, v get X+1. Performing step 4, v get (X+1)250, that is (X250+250). Assuming “y” is to be the last 4 digits. Performing step 5 and 6, v get (x250+250+2y). now performing step 7, v get (x250+2y). It is like the step 3 and 7 are nullifying each other. So, v can safely remove both, step 3 and 7. So v get 1. Take first 6 numbers of any cell number 2. Multiply with 80 3. Multiply with 250 4. Add the last 4 digits of ur number 5. Again add the last 4 digits ur number 6. Divide by two The result will still be the same. Now combine step 1 and 2, instead of multiplying with 80 and then by 250, v can directly multiply by 20000. The net effect is that the six digit number is multiplied by 2 and then moved to the right by 4 digits. Now v add twice the last 4 digits. Why twice the last 4 digits? It can be only once also, if the 6 digits are multiplied with a net effect of 10000. But it is not so. It is multiplied by twice of 10000. This twice is again removed altogether in step 6. That is u can safely remove the last step 6. U will get 1. Take first 6 numbers of any cell number 2. Multiply with 10000 3. Add the last 4 digits of ur number In these three steps, whatever 10 digit number u take, u get the same number. This is the basis of the trick. It is one of the oldest trick in the oldest book. Regards Rangarajan.K	"

mahesh (Tax Consultant) (78 Points)
Replied 10 September 2008

Originally posted by :Subodh
"	I have not get the answer of this process. Here is a math trick so unbelievable that it will stump you. Personally I would like to know who came up with this. It is Pretty Amazing. 1. Grab a calculator. 2. Key in the first six digits of your mobile number ( India mobile No only) 3. Multiply by 80 4. Add 1 5. Multiply by 250 6. Add the last 4 digits of your phone number (Not the total of 4 digits.) 7. Add the last 4 digits of your phone number again. (Not the total of 4 digits.) 8. Subtract 250 9. Divide number by 2 Do you recognize the answer? Thanking you in anticipation.	"