Polygons

A polygon is a closed two-dimensional shape with straight sides. The word "polygon" comes from the Greek words "poly," meaning "many," and "gonia," meaning "angle." This tells us that polygons are shapes with many angles.

Characteristics of Polygons

Some key characteristics of polygons include:

Vertices: Polygons have vertices, which are the points where the sides of the polygon meet.
Sides: The sides of a polygon are the straight line segments that form the boundary of the shape.
Interior Angles: Each interior angle of a polygon is formed by two adjacent sides and lies inside the polygon.
Exterior Angles: The exterior angles of a polygon are formed by extending one side of the polygon and the adjacent side.

Types of Polygons

There are many different types of polygons, some of the most common include:

Triangle: A polygon with three sides and three angles.
Quadrilateral: A polygon with four sides and four angles.
Pentagon: A polygon with five sides and five angles.
Hexagon: A polygon with six sides and six angles.
Octagon: A polygon with eight sides and eight angles.

Regular and Irregular Polygons

Polygons can be further classified as regular or irregular:

Regular Polygon: A polygon with all sides of equal length and all angles of equal measure.
Irregular Polygon: A polygon with sides and/or angles of different lengths and measures.

Area and Perimeter of Polygons

Calculating the area and perimeter of polygons involves different formulas depending on the type of polygon. For example, the area of a rectangle is calculated using the formula A = length × width, while the perimeter is calculated using the formula P = 2 × (length + width).

Understanding polygons is important in geometry and helps us describe and analyze various shapes in our world.

◂Math Worksheets and Study Guides First Grade. Odd and Even

Identifying Even and Odd Numbers

The resources above cover the following skills:

Number and Operations (NCTM)

Understand numbers, ways of representing numbers, relationships among numbers, and number systems.

Count with understanding and recognize 'how many' in sets of objects.

Develop a sense of whole numbers and represent and use them in flexible ways, including relating, composing, and decomposing numbers.

Connect number words and numerals to the quantities they represent, using various physical models and representations.

Grade 1 Curriculum Focal Points (NCTM)

Number and Operations: Developing an understanding of whole number relationships, including grouping in tens and ones

Children compare and order whole numbers (at least to 100) to develop an understanding of and solve problems involving the relative sizes of these numbers. They think of whole numbers between 10 and 100 in terms of groups of tens and ones (especially recognizing the numbers 11 to 19 as 1 group of ten and particular numbers of ones). They understand the sequential order of the counting numbers and their relative magnitudes and represent numbers on a number line.

Connections to the Grade 1 Focal Points (NCTM)

Algebra: Through identifying, describing, and applying number patterns and properties in developing strategies for basic facts, children learn about other properties of numbers and operations, such as odd and even (e.g., 'Even numbers of objects can be paired, with none left over'), and 0 as the identity element for addition.