Try this. Its accurate….

1) key-in the first 3 digits of your handphone number (exclude the '9') into the calculator
2) multiply by 80
3) add 1
4) multiply by 250
5) plus last four digits of phone number
6) plus last four digits of phone number again
7) minus 250
8) divide by 2 at last

It is your handphone number!!!

I am still trying to figure out how to key in 006 into the calculator :P