Number-Bond Cards for Multiplication and Division - Singapore Math (Crystal Springs Books) Crystal Springs Singapore Math Manipulative Grades 3 through 6 Illustrates the relationships between numbers and inverse relationship between multiplication and division Builds fluency and gain number sense at the same time 82 cards Crystal Springs Singapore Math Manipulative Grades 3 through 6 Illustrates the relationships between numbers and inverse relationship between multiplication and division Builds fluency and gain number sense at the same time 82 cards