Answer

            If you observe the phone numbers of each of the given places, you can certainly find all these numbers follow a definite criterion and we bet you have worked it out! If not then let’s make it out together! Let’s take the first set of numbers. All the numbers have same first seven digits identical (612 8232) and the ones that vary are the last four digits only. Similarly if we take the case of Ireland, the first five digits are identical (353 01) and the ones that vary are the last seven digits. Same is the case if we see the other numbers (Algeria, UAE, Peru, and Bolivia). Not only this, if you go nay where in the world, the general trend is this. The maximum number of digits that vary is 7 (in general). Now think why???

Why is it that even though the phone number is too big, only the last few digits are different to identify a particular telephone set (or cellular mobile phone)?

Did the bulb glow in your mind?

No?

The reason is simple! Many research conducted on the normal capacity of human brain to hold things have prescribed that the maximum number of things that a normal human brain can hold is seven plus/minus two. And we bet, you would definitely not like to stand in front of a telephone booth and guess the telephone number and also get shouted at if it is a wrong number!!