The Number Line in the Common Core

CONTENTS OF CURRICULUM UNIT 16.05.02

  1. Unit Guide
  1. Introduction
  2. Getting Started Right is Important
  3. Linear Measurement
  4. The Number Line
  5. Mathematical Practices
  6. Teaching Strategies
  7. Classroom Activities
  8. Resources
  9. Endnotes
  10. Appendix - Implementing District Standards

Using the Number Line in Second Grade

Carol P. Boynton

Published September 2016

Tools for this Unit:

Getting Started Right is Important

As was mentioned earlier, before students can grasp the second grade Common Core State Standards in Mathematics (CCSSM), they must first be prepared and have a firm grip on the standards in place for first grade.  Because all later mathematics builds on this earlier learning, it is important that students have a good start.  In particular, students should have a good start in arithmetic.1  They need to develop a broad conceptual understanding of the operations of addition and subtraction such that it can ultimately be applied across contexts; they should recognize the connection of arithmetic to geometry through measurement

In Roger Howe's paper Three Pillars of First Grade Mathematics, and Beyond, he identifies and explains the "three main ingredients that are key to starting off right."2

I) A robust understanding of the operations of addition and subtraction.

II) An approach to arithmetic computation that intertwined place value with the addition/subtraction facts.

III) Making connections between counting number and measurement number.

Addition and subtraction are introduced in Kindergarten.  Students use a variety of manipulatives to develop an understanding of putting together, addition, and taking away, subtraction.  This practice prepares children with experiences of not only using the materials but learning the vocabulary necessary to discuss and further understand the operations of addition and subtraction.  Upon entering first grade, students begin the intensive instruction in mathematics, with the CCSSM using place value understanding and properties of operations to add and subtract within 100 (1.NBT.C.4).  This expands to adding and subtract within 1000 once the students move on to second grade (2.NBT.B.7). 

Comments:

Jahiderles Yudith Ching Castillo

October 2, 2022 at 7:55 pm

Excellent progression from concrete to pictorial.

I will embed the sentence strips and base ten blocks to explain another way to add coins. I explained this week to my colleagues that the number line can even be used as a visual representation to add coins. We agreed that as long as we clarify to the students what units are involved (cents), this will not confuse students when they get to higher grade levels and have to work with decimals. Meaning, the 1 will represent a dollar and the intervals will be 1/10 of a dollar. This article also gave me the idea of using the Cousinaire rods to introduce the term multiples. The collaborative work that can be done among students exploring Cousinaire rods is extraordinary in the sense of developing conceptual understanding of units of measurement, relationships, and patterns.

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