do the math

/D UW1 DH AH0 M AE0 TH/
verb
  1. 1

    (chiefly US) To perform a mathematical calculation.

  2. 2

    (chiefly US) To determine the explanation for or precise nature of a situation, such as the motive underlying someone's behavior, based on available facts.

Source: https://en.wiktionary.org/wiki/do%20the%20math