Yes, на can mean both division and multiplication depending of context. But if there is no any context, I would interpret it as multiplication by default.
There are a lot of defaults in math, for example operation priorities with standard functions:
sin 2 x = sin(2*x)
sin x cos x = (sin(x)) * (cos(x))
You are not only saying in in a same way (without any operation), but you are also writing it in a same way - without brackets.