First grade students begin to develop the concept of place value by viewing 10 ones as a unit called a ten. This basic but essential idea is the underpinning of the base-ten number system.
4 Critical Areas of Instruction
In first grade, instructional time focuses on four critical areas: (1) developing understanding of addition, subtraction, and strategies for addition and subtraction within 20; (2) developing understanding of whole-number relationships and place value, including grouping in tens and ones; (3) developing understanding of linear measurement and measuring lengths as repeating length units; and (4) reasoning about attributes of shapes and composing and decomposing geometric shapes (National Governors Association Center for Best Practices, Council of Chief State School Officers [NGA/CCSSO] 2010). Students also work toward fluency in addition and subtraction with whole numbers within 10.
When educators talk about doing an operation “within” a number, for example “within 10”, they mean the answers are no larger than 10. Being fluent with something in math means students can do the operation reasonably fast and accurately. For most first grade students, this means they have memorized the addition and subtraction facts within 10.