Probably a silly question, but I can't figure it out.
Why is magnetic flux defined as magnetic field strength per unit area if it is found by multiplying the strength of magnetic field B by area A rather than dividing by area A?
I think you have your terms confused. You know that a magnetic field can be represented by lines of force?
The closer the lines are the stronger the force and therefor a 'sensible' unit for magnetic FIELD STRENGTH would be 'lines per square metre'
Historically 'lines' were called Webers and therefore magnetic field strength can be given as Webers per square metre. 1 Weber per square metre is now called 1 Tesla so magnetic field strength is given in Tesla.
Magnetic field strength is also known as 'magnetic flux density' and the symbol is B.
Magnetic FLUX is flux density x Area and is given in Webers
Flux = B x A
Hope this helps .... The units in magnetism are not very user friendly