Have a look at the house plan at bottom with five rooms and sixteen doors in total. The intention is to make a run through the rooms and pass each of the sixteen doors exactly once. Now the question is what is the route to run.
It would be somthing like this.
By using the numbers 8,5 1 and 1 exactly once and with the help of basic operation (+, -, /, *), Can you form an expression with a value of 10?
Note: Parentheses are allowed