One way to view this is that while the "act of performing" mathematics happens in a physical world, the results as such are unrelated to time.
Below is written from a specific pedestrian view of mathematics, and is partly arm-chair philosophy.
Similarly to one playing a specific piece from sheet music, the sheet music is an invariant of time, while the act of performance, is, yes, very much time related.
I think what you mean is the act of performing the computation 1+1 always takes some time, what mathematically is generally understood as relevant is the relationship 1+1 itself, which does not really change.
We can change the numbers so we don't know the result beforehand, but that does not mean the end result would change - it does not, as long as the rules don't change.
The relationship of the diameter of a circle and the the circumference is always pi. We can take any number of of circumferences and diameters, and given one or another is unknown, we may need to do some computations to know for example the circumference of a wheel with a diameter of 2.
While we need to perform the computation pi * 2, the result itself actually never changes, and is irrelevant of time -an eternal truth so to speak, crystallized forever in the fundamental logical nature of our reality.
Or, another example, if we take a right triangle, say with the Egyptian famous example with side lengths of 3,4, and 5, it gives us many more invariants that don't change no matter how many times you perform any computation.
Given a right triangle with non-hypotenuse sides 3 and 4, the hypotenuse is always a length of 5. No matter how many times we perform the computation, for example, sqrt(3*3 + 4*4) - the end result is something timeless.
Pythagorean theorem holds for all planar right triangles, for all eternity, and everywhere, Acapulco or for example on a some desolate rock circling a star in Magellanic Clouds 2 million years ago.
While "Pythagorean theorem" is just a name given to a specific logical relationship, the logical relationships described by the theorem do not change. They are eternal.
Discovering Pythagorean theorem certainly took time.
One view of mathematics is that it's just a way to navigate a vast logical landscape of logical relations that are invariant of time or space. That the act of "performing" mathematics is navigating a static landscape crystallized beyond space and time, into a fundament.
Others view mathematics as just a logical game. Never the less, even there with fixed rules, specific input will always result in specific output.
