Finding denominators of equivalent fractions. Math walk the plank interactive online fun game. This game is an interactive online test for children to practice their skills on fractions: what is an equivalent fraction, what is the denominator ? how do we find the denominator ? Each game has multiple choice answers to problems. These games are suitable homeschool and classroom practice for children in Kindergarten, 1st, 2nd, 3rd, 4th, 5th, 6th and 7th grades. Click start and begin practicing.