If I use the calculator provided by Google search, I can enter the expression
3% + 3%
and it tells me the answer is 0.0309. I would think that 3% is the same as .03, which should make the answer .06, no? Am I misunderstanding what I'm asking of the calculator?
I get the same behavior on my phone's app (of course, it is an Android phone so perhaps shouldn't be surprising). But on my Windows PC the built in calculator doesn't even let me enter 3% as an operand. It immediately changes it to zero.
My underlying question is how can 3% + 3% equal .0309?
If $3$% to enlarge on $3$% we'll obtain $0.0309$
because $$0.03\cdot\left(1+\frac{3}{100}\right)=0.0309.$$