Practice finding denominators of equivalent fractions En garde math games for, 3rd, 4th, 5th, 6th grade children. Math En garde interactive online fun game. This game is an interactive online test for children to practice their skills on finding denomenators of fractions. Each game has multiple choice answers to problems. These games are suitable homeschool and classroom practice for children in 3rd, 4th, 5th, 6th and 7th grades. Click start and begin practicing.