Common Core Essential Elements Mathematics

GLOSSARY AND EXAMPLES OF MATHEMATICS TERMS 
Acute triangle. 
A triangle with all acute angles (acute means measuring less than 90°).  See 
Hhttp://www.mathsisfun.com/definitions/acute-triangle.html 
Angles. 
A shape formed by two lines or rays that diverge from a common point or vertex. 
Area.
 The size of a region enclosed by the figure.  Area is measured in square units (e.g., the area of this rectangle is six square 
units). 
 
 
 
 
 
 
 
 
 
Associative property for addition. 
The sum of three or more numbers which are always the same when added together, no matter 
what order they are in.  This is illustrated by 
a 
+ (
b 
+ 
c
) = (
a 
+ 
b
) + 
c
;
 
2 + (3 + 4) = (2 + 3) + 4.