The following terms appear in this grade level's materials. At this grade level the terms are used within one or more examples or illustrations. The purpose is to begin to develop the basic concept,
which will be more formally developed in coming grades.

ADDITION (WHOLE NUMBER)  LENGTH  SUBTRACTION 
CIRCLE  MEASUREMENT (LENGTH)  SYMBOLS FOR ADDITION 
CONCEPT OF ZERO  RECTANGLE  THREE DIMENSION 
CONE  SHAPE  TRIANGLE 
COUNTING  SIZE  WEIGHT 
CUBE  SPHERE  WRITING NUMBERS 
CYLINDER  SQUARE  
  
  
  
  
  
A synonym of the following terms has been used. The synonym helps to bridge the learner's non mathematical experiences to mathematics terms that will more formally be worked on.
A synonym may also be used because these historical terms may have been replaced by a new vocabulary (k12math.info's list of 1,000 terms has not changed in 40 years).
Wiktionary dictonary may help here.

COMPARISON (MEASUREMENT)  EQUALITY  INEQUALITY 
NUMBER SENTENCE  PROBLEM SOLVING  
  

K12math.info selected the content that appears here. All terms appear in the lesson proper. The selection process is based upon a content analysis of 2013 to advance copies of 2015 student mathematics
textbook series. Series that base their content on 2010 and/or 2012 standards. The analysis also included content that was felt would be needed for the
transistion to CK12 existing textbook series.
Editor's Note: This is a very basic outline of the content and how they are to be developed in the lesson proper. These terms need to be used in examples, illustrations, class activities and homework to help further understand them.
Resources:
Learners age 5 to 11 Grades K through 6 (from Wikieducator's "Come fly with me..." project).
Key points in Writing a textbook. (Especially step 7)
Teaching OER Mathematics.
Learning design a Wikieducator.org project.
Additional observations made while collecting information for this site on unit development in a textbook:
 One type has a chapter unit divided into 3 parts:
Part 1 has a written explanation of the concept being developed (or defined).
Part 2 has examples and illustrations of the concept.
Part 3 classroom and/or homework activities.
 Another approach consists of 2 parts:
Part 1: the concept being developed (or defined) is being used in several carefully designed examples and illustrations.
Part 2: classroom and/or homework activities.
