1 / 16

# Addition of Real Numbers - PowerPoint PPT Presentation

Addition of Real Numbers. Section 1.6 (42). Objectives (41). Add real numbers using the number line Add fractions Identify opposites (additive inverses) Add using absolute values Note: We don’t cover Using Calculators. 1.6.1 Add Real Numbers Using a Number Line (41).

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Section 1.6

(42)

Objectives(41)

Add real numbers using the number line

Note: We don’t cover Using Calculators

We first locate the first point.

If we add a positive number, we move over that number of units to the right.

If we add a negative number, we move over that number of units to the left.

Example: -2 + ( +3 )

-4 -3 -2 -1 0 1 2 3 4

o

- - - 3 - -x

1

+3 + (-5)

-4 -3 -2 -1 0 1 2 3 4

o

x - - - - 5 - - - - -

-2

-2 + (+2)

-4 -3 -2 -1 0 1 2 3 4

o

- - - - x

0

A miner descents 120 feet down a mine shaft. Later, he descends another 145 feet. Find the depth of the descent.

Given: Initial 120 feet down (-120)

Later 145 feet further down (-145)

Find: Total distance down

How: Add initial and distance down

Solve: -120 + ( -145 )

If we add two negative numbers, we add the absolute values and put a minus in front.

-120

+ -145

-265

The miner would have descended 265 feet (-265)

When you add fractions, you MUST have the same denominators.

You have to find the LCD and create equivalent fractions with that denominator.

Example:

1/2 + 2/3 LCD = 6

1/2 (3/3) + 2/3 (2/2)

3/6 + 4/6 = (3 + 4)/6 = 7/6 = 1 1/6

Examples number line.

5/8 + (-6/7) LCD 56

5/8 (7/7) + (-6/7) (8/8)

35/56 + (-48/56)

[ +35 + (-48) ] / 56

-13/56

1/8 + ( -7/12 ) LCD 24

1/8 (3/3) + (-7/12) (2/2)

3/24 + (-14/24)

[ +3 + (-14)] / 24

-11/24

1.6.3 Identify Opposites number line.(44)

The purpose for opposites is to determine which value to add to make the sum equal 0.

They are better known as additive inverses.

The additive inverse is the same value with the opposite sign.

Examples:

the opposite of 3.5 is -3.5

the opposite of -3/4 is +3/4

the opposite of 0 is 0

1.6.4 Add Using Absolute number line.Values(44)

Same sign:

To add two numbers with the same sign (either both positive or both negative), add their absolute values and use the same sign.

Examples:

( +10 ) + ( +5 ) = +15

( -9 ) + ( +5 ) = -4

Using number line.Absolute Values (cont)(44)

Different signs.

To add two numbers with different signs (one positive, the other negative), subtract the absolute value of the smaller from the absolute value of the larger and use the sign of the larger.

Examples:

( -9 ) + ( +4 ) = -5

( -2 ) + ( +8 ) = +6

Examples number line.

-1/4 + ( +3/4)

-2/4 = -1/2

5/6 + ( -1/9 ) LCD 18

5/6 ( 3/3) + ( -1/9 ) ( 2/2)

15/18 + ( -2/18 ) = +13/18

-2/5 + ( +1/4 ) LCD 20

-2/5 ( 4/4) + ( +1/4 ) ( 5/5 )

-8/20 + ( + 5/20 ) = -3/20

Example number line.

A bakery had a profit of \$450,567 for the first five months of the year, and a loss of \$52,987 for the remainder of the year. Find the net-profit or loss for the year.

Given: \$450,567 profit Jan – May

\$52,987 loss Jun – Dec

Find: Net-profit or loss for the year

How: Add the values from each set

Solve: 450,567 + ( -52,987 )

450,567 Since they are different signs, number line.

-52,987 subtract absolute values and

397,580 use the sign of the larger

Solution: There was a net-profit of \$397,580 for the year.

Objectives number line.(41)

Add real numbers using the number line

Note: We don’t cover Using Calculators

Section 1.6

(42)