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Counting on the Number Line

Instructor: Audrey Akins

Audrey has more than a decade of experience teaching elementary. She has a bachelor's in journalism and a master's in education.

By now, you've probably learned to use different things to help you solve problems. In this lesson, you'll learn how to count on a number line when you're adding, subtracting, and multiplying.

Using a Number Line to Add

When you're adding, you may already have a strategy in mind, such as counting up or drawing a picture. Another way to add is to use a number line, or a straight line made up of evenly spaced parts.

When using a number line to add, find the first number in your addition sentence on the line. Then, move as many spaces to the right as shown in the second number in your number sentence. For example, if you have 7 crayons in your box, and then find 2 more on the floor, your addition sentence is 7 + 2 = _____. Find the number 7 on the number line, and then move to the right two times to find the answer: 7 + 2 = 9.

Move to the right on the number line when adding.
number line add

Using a Number Line to Subtract

When you use a number line to subtract, you'll move to the left, instead of the right, on the line. For example, when you first got your box of crayons, you had 10 crayons. When you get ready to put them back in the box, you notice that 4 are missing. In this situation, your number sentence is 10 - 4 = _____.

To solve this problem on a number line, start at 10, and move 4 spaces to the left. The number you end on, 6, is your answer.

Move to the left on the number line when you
number line sub

Using a Number Line to Multiply

Along with using a number line to add and subtract, you also use it to multiply, which is just repeated addition. Say you have 3 friends, and they each have 4 erasers. In order to determine how many erasers they all have, skip count in sections by the number you're multiplying by, in this case 4.

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