This week, students practiced additional addition and subtraction strategies, including “make a ten.” Knowing how to make a ten is a fundamental skill to understanding our base-ten system.  Through the use of counters, unifix cubes, ten frames, and numerous games, students explored combinations of ten.  Knowing combinations of tens will aid first graders in solving related facts as well as algebraic equations.  For example, knowing 2 + 8 = 10 makes it easier to understand that 20 + 80 = 100, and that 32 + 48 = 80.

Students are also working to identify fact families, or a group of facts that use the same set of numbers with inverse operations such as 6 + 4 = 10, 4 + 6 = 10, 10 – 6 = 4, and 10 – 4 = 6.  Using combinations of 10 in this way helps students to solve related facts including algebraic expressions, in which students solve for the missing addend.  As we practice these strategies in the classroom, students will be playing a variety of games, looking for patterns, manipulating objects, writing number sentences, and solving equations.  Next week, we will learn “fast tens.”  Just as when working with counting on, counting back, doubles facts, etc., our goal is to memorize our addition and subtraction facts to become faster and more efficient at manipulating numbers.