23Adding and Subtracting Integers

1
2-3 Adding and Subtracting Integers

• Algebra One
• CP2

2
Absolute Value

• The absolute value of a number is its distance
  from zero on the number line. Since distance is
  always positive, the absolute value of a number
  is always positive.
• -5 5 5 5
• ½ ½ -½ ½

3
Rules for adding signed numbers

• When adding numbers with the same signs, add the
  absolute value of each number and take the common
  sign.
• When adding numbers with different signs,
  subtract the smaller absolute value from the
  larger absolute value and take the sign of the
  larger absolute value.

4
Additive Properties

• Additive Identity Property (Add. ID. Prop.)
• Adding zero to any number will not change the
  value of that number.
• a 0 a
• The additive identity is zero.
• Additive Inverse Property (Add Inv. Prop.)
• Adding a number to its inverse will result in
  zero.
• a (a) 0
• If two numbers are opposites, they are additive
  inverses
• of each other.

5

• Simplify. State thought process (Add/ Subtr/
  Add ID Prop./Add Inv. Prop.)

6
Subtraction Rule

• To subtract, change to adding the opposite and
  then follow the rules for adding signed numbers.
• Keep Change Opposite

7

• Simplify. Show you are using the subtr. rule
  and state thought process (Add/ Subtr/ Add ID
  Prop./Add Inv. Prop.)

8

• Evaluate if w 14, x -8, and y -10.
  State thought process (Add/Subtr.)