Global Lehigh Strategic Initiatives (without descriptions)
7.4 adding real numbers with the same sign
1. Adding Real Numbers—Number Line Method
GUIDED EXAMPLE 1 Find the total value of the withdrawals for
the day.
You write a check for $30 at dinner, and then later you write a
check for $10 at the movies.
SOLUTION
STEP RESULT
Represent the
withdrawal of $30
on a number line.
Represent the
withdrawal of $10
on the number line.
Determine the total
withdrawal.
Answer The total value of the withdrawals is
2. Adding Real Numbers—The Chip Method
GUIDED EXAMPLE 2 Add.
SOLUTION
STEP RESULT
Represent with chips.
Represent with chips.
Represent the addition with chips.
Add the chips.
Answer
3. Adding Real Numbers with the Same Sign
GUIDED EXAMPLE 3 Add.
SOLUTION
STEP RESULT
Add the numerical parts.
Give the answer the sign of the
numbers being added.
Answer
Both numbers are negative, so the
sign of the sum is negative.
4. Adding Real Numbers with the Same Sign
GUIDED EXAMPLE 4 Add.
SOLUTION
STEP RESULT
Add the numerical parts.
Give the answer the sign of
the numbers being added.
Answer
Both numbers are negative,
so the sign of the sum is negative.
5. Adding Real Numbers with the Same Sign
GUIDED EXAMPLE 5 Add.
SOLUTION
STEP RESULT
Add the numerical parts.
Give the answer the sign of the
numbers being added.
Answer
Both numbers are negative,
so the sign of the sum is negative.
6. Adding Real Numbers with the Same Sign
GUIDED EXAMPLE 6 Add
SOLUTION
STEP RESULT
Add the numerical parts.
Give the answer the sign of the
numbers being added.
Answer
All three numbers are negative,
so the sign of the sum is negative.
7. Study Guide
The absolute value of a number is the distance between
that number and zero on a number line.
Procedure: ADDING TWO NUMBERS WITH THE SAME SIGN
To add two numbers of the same sign, add the absolute values, or
numerical parts, of the numbers and give the answer the same sign as the
numbers being added.
Note: A number written without a sign is assumed to be positive.
