6.211 In life it is indeed never the mathematical proposition that we need, but rather we use mathematical propositions only in order to infer from propositions that do not belong to mathematics to others that likewise do not belong to mathematics.

(In philosophy the question “To what end do we really use this word, that proposition” leads time and again to valuable insights.)

So, for instance, “I have to give Jo this five-dollar bill” is not part of mathematics, but we might use mathematics to reach this practical conclusion from “Jo gave me a ten-dollar bill for this five-dollar soup and focaccia.” “Meaning is use” here as a guiding principle.