A number line is a visual representation of numbers in order. It is a line on which all numbers are positioned according to their value. The number line extends infinitely in both directions, representing all positive and negative numbers as well as zero.

The number line is typically marked with equally spaced points or ticks, with integers placed at regular intervals. It helps in understanding the relative magnitude of numbers and their position in relation to one another.

For example, on a number line, the number 0 is placed in the middle, with positive numbers to the right and negative numbers to the left. As we move to the right, the numbers increase, and as we move to the left, the numbers decrease.

Number lines are frequently used in elementary mathematics to teach concepts such as addition, subtraction, and understanding the concept of positive and negative numbers. They are also used to visually represent fractions and decimals.

Overall, the number line is a valuable tool for understanding and visualizing numerical relationships and is a fundamental concept in mathematics.

Study GuideSubtraction Facts Worksheet/Answer key

Subtraction Facts Worksheet/Answer key

Subtraction Facts Worksheet/Answer key

Subtraction Facts Worksheet/Answer keySubtraction Facts Worksheet/Answer keyAddition and Subtraction Vocabulary/Answer keySubtraction Facts

Number and Operations (NCTM)

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

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.

Understand meanings of operations and how they relate to one another.

Understand various meanings of addition and subtraction of whole numbers and the relationship between the two operations.

Understand the effects of adding and subtracting whole numbers.

Compute fluently and make reasonable estimates.

Develop and use strategies for whole-number computations, with a focus on addition and subtraction.

Develop fluency with basic number combinations for addition and subtraction.

Algebra (NCTM)

Represent and analyze mathematical situations and structures using algebraic symbols.

Use concrete, pictorial, and verbal representations to develop an understanding of invented and conventional symbolic notations.

Use mathematical models to represent and understand quantitative relationships.

Model situations that involve the addition and subtraction of whole numbers, using objects, pictures, and symbols.

Grade 1 Curriculum Focal Points (NCTM)

Number and Operations and Algebra: Developing understandings of addition and subtraction and strategies for basic addition facts and related subtraction facts

Children develop strategies for adding and subtracting whole numbers on the basis of their earlier work with small numbers. They use a variety of models, including discrete objects, length-based models (e.g., lengths of connecting cubes), and number lines, to model 'part-whole,' 'adding to,' 'taking away from,' and 'comparing' situations to develop an understanding of the meanings of addition and subtraction and strategies to solve such arithmetic problems. Children understand the connections between counting and the operations of addition and subtraction (e.g., adding two is the same as 'counting on' two). They use properties of addition (commutativity and associativity) to add whole numbers, and they create and use increasingly sophisticated strategies based on these properties (e.g., 'making tens') to solve addition and subtraction problems involving basic facts. By comparing a variety of solution strategies, children relate addition and subtraction as inverse operations.

Connections to the Grade 1 Focal Points (NCTM)

Number and Operations and Algebra: Children use mathematical reasoning, including ideas such as commutativity and associativity and beginning ideas of tens and ones, to solve two-digit addition and subtraction problems with strategies that they understand and can explain. They solve both routine and nonroutine problems.