First, let's divide the forty-two into six parts. How much is each part? This result is multiplied by three (because three-sixths is three times one-sixth), and the result is three-sixths of forty-two.

Six copies of forty-two are equal to 42÷6=7, and then 7×3=2 1, that is to say, 3/6 of forty-two is 2 1.