Adding Integers on a Number Line

Adding integers

By Michael Libron

Addition problems can be solved easily using the number line.

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Example: -1 + (-1) = -2

The first integer is the starting point of the model and the second integer would serve as the number of units you will move from the first number. The direction of the movement depends on the sign of the second number. If the second number is NEGATIVE the movement is towards to the left. If the second number is POSITIVE, the movement is towards to the right of the first number.

Adding integers using the number line

Poll

Which number models 4 + (-9)? What is the sum?

• Number line A

  The sum is -9

• Number line A

  The sum is -4

• Number line B

  The sum is -5

• Number line B

  The sum is -4

Multiple Choice

What is the addition problem described in the number line?

• -7 + 1 = -6

• -6 + (-1) = -7

• -7 + 1 = 6

• The answer is not the other options.

Multiple Choice

What is the sum in the problem illustrated in the number line?

• -5

• -6

• 1

• -1

Adding integerd using the rules:

​The sum of two positive integers is a POSITIVE INTEGER.

5 + 6 = 11

Some text here about the topic of discussion

​The sum of two negative integers is a NEGATIVE INTEGER.

-5 + (-6) = -11

Adding integerd using the rules:

​To find the sum of a positive and a negative integer , subtract them and reflect the sign of the number with bigger absolute value.

5 + (-6) = -1

Some text here about the topic of discussion

Multiple Choice

Find the sum: -5 + (-7)

• -12

• 12

• 2

• -2

Draw

What is the sum of -4 + 5 + 1?