Why would they necessarily even compose 2+2=4? This seems very intuitive and obvious to you, does pic related seem obvious to you? It is insane to think that aliens would have a math system where the line integral over a positively oriented, piecewise smooth, simple closed curve in a plane of functions L and M equal the double integral over the plane region bounded by the curve!
Why would aliens not use different axioms that also have some approximation to reality that we may not see? 2+2 may equal 4 in this alien mathematic but it may be a complex theorem as opposed to a basic result.
A plant always held the characteristics of being able to grown in groups, and soft flesh easy to cut, and yummy to humans, so was farming discovered, or invented? Spacetime always held the property of masses attracting each other, but is our 'finding' this discovery, or is our (not necessarily true) analysis of this phenomenon an invention? The same way two 'separate' objects always could be grouped to find 2 of them to get the sum 1+1=2.