Truth is the label we apply to claims that match reality. Therefore, a claim is either true or it's not true.
Just because certain terms are conditional or relative (such as words like "tall" or "good") doesn't mean that the truth is nebulous. It just means we have to specifically know what is meant when someone says "tall" or "good" before we can asses whether or not their claim matches reality.
Words don't have intrinsic meanings. They have usages.
-Matt Dillahunty
As a side note - mathematics in and of itself is never true or false. As an abstraction, it can only ever be accurate or inaccurate just like claims about the force in Star Wars could only ever be accurate or inaccurate. In order for mathematics to be true or false it has to be in relation to something in the real world. For example, if I take these two oranges and put them with those two oranges then I will have a total four oranges - would be true. But 2+2=4 isn't true - it's accurate.