## 21 March 2018

### How old are you? (version 1)

For those born in the $20$th century.

Think of a number from $1$ to $7$.

With the help of this secret number, you will do five operations. You will get something very revealing about yourself.
1. Multiply this number by $2$.
2. Add $2$.
3. Multiply the result by $50$.
4. If your birthday has already passed this year, add $18$, otherwise add $17$.
5. Subtract the last two digits of the year of your birth.
The result is a three digit number. The first one is the number that you thought and the last two are ... your age!

Note: This astuteness is valid for the year $2018$. For $2019$, you must add one unit to the numbers referred in point 4. For $2020$, two units and so on.