The magnetic field in a certain region is given by B=<40i-18k>T. How
much flux passes through a 5cm^2 area loop in this region if the loop
lies flat in the xy plane?
The Attempt at a Solution
I got the answer (90 * 10^-4) in negative, and its in positive in the textbook at the back...
How can flux be negative and why can we drop the negative sign?