hahahah, ehsan, man, that was hilarious.
a much simpler version of that would be to do the following:
1. Multiply first 3 digits by 10,000
2. Add last 4 digits
This is algebraically equivalent to what you just did.
Proof:
Let x = 'first 3 digits of telephone number'
Let y = 'last 4 digits of telephone number'
The steps as proposed by ehsan:
1. 80x
2. 80x + 1
3. (80x + 1)250
4. (80x + 1)250 + y
5. (80x + 1)250 + 2y
6. (80x + 1)250 + 2y - 250
7. ((80x + 1)250 + 2y - 250)0.5
Simplification of the above:
((80x + 1)250 + 2y - 250)0.5 = (20,000x + 250 + 2y - 250)0.5
= (20,000x + 2y)0.5
= 10,000x + y
The fact that I went through the trouble to post this shows that I am a lame idiot who has nothing better to do on Eid day. :P
|