This takes less than a minute. Get hold of a calculator and work it out as you read.

First of all, pick the number of times a week that you would like to go out to eat (more than once but less than 10)

Multiply this number by 2 (just to be bold)

Add 5

Multiply it by 50

If you have already had your birthday this year add 1758… if you haven’t, add 1757.

Now subtract the four digit year that you were born.
You should have a three digit number… The first digit of this was your original number. (i.e. how many times you want to go out to restaurants in a week.)
The next two numbers are your age.