# 1.3 Add and subtract integers  (Page 7/10)

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## Practice makes perfect

Use Negatives and Opposites of Integers

In the following exercises, order each of the following pairs of numbers, using<or>.

$9___4$
$-3___6$
$-8___-2$
$1___-10$

> < < >

$-7___3$
$-10___-5$
$2___-6$
$8___9$

In the following exercises, find the opposite of each number.

2
$-6$

$-2$ 6

9
$-4$

In the following exercises, simplify.

$\text{−}\left(-4\right)$

4

$\text{−}\left(-8\right)$

$\text{−}\left(-15\right)$

15

$\text{−}\left(-11\right)$

In the following exercises, evaluate.

$\text{−}c$ when
$c=12$
$c=-12$

$-12$ 12

$\text{−}d$ when
$d=21$
$d=-21$

Simplify Expressions with Absolute Value

In the following exercises, simplify.

$|-32|$
$|0|$
$|16|$

32 0 16

$|0|$
$|-40|$
$|22|$

In the following exercises, fill in<,>, or $=$ for each of the following pairs of numbers.

$-6___|-6|$
$\text{−}|-3|___-3$

< $=$

$|-5|___\text{−}|-5|$
$9___\text{−}|-9|$

In the following exercises, simplify.

$\text{−}\left(-5\right)\phantom{\rule{0.2em}{0ex}}\text{and}\phantom{\rule{0.2em}{0ex}}\text{−}|-5|$

$5,-5$

$\text{−}|-9|\phantom{\rule{0.2em}{0ex}}\text{and}\phantom{\rule{0.2em}{0ex}}\text{−}\left(-9\right)$

$8|-7|$

56

$5|-5|$

$|15-7|-|14-6|$

0

$|17-8|-|13-4|$

$18-|2\left(8-3\right)|$

8

$18-|3\left(8-5\right)|$

In the following exercises, evaluate.

$\text{−}|p|\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}p=19$
$\text{−}|q|\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}q=-33$

$-19$ $-33$

$\text{−}|a|\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}a=60$
$\text{−}|b|\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}b=-12$

In the following exercises, simplify each expression.

$-21+\left(-59\right)$

$-80$

$-35+\left(-47\right)$

$48+\left(-16\right)$

32

$34+\left(-19\right)$

$-14+\left(-12\right)+4$

$-22$

$-17+\left(-18\right)+6$

$135+\left(-110\right)+83$

108

6 $-38+27+\left(-8\right)+126$

$19+2\left(-3+8\right)$

29

$24+3\left(-5+9\right)$

Subtract Integers

In the following exercises, simplify.

$8-2$

6

$-6-\left(-4\right)$

$-5-4$

$-9$

$-7-2$

$8-\left(-4\right)$

12

$7-\left(-3\right)$

$44-28$
$44+\left(-28\right)$

16 16

$35-16$
$35+\left(-16\right)$

$27-\left(-18\right)$
$27+18$

45 45

$46-\left(-37\right)$
$46+37$

In the following exercises, simplify each expression.

$15-\left(-12\right)$

27

$14-\left(-11\right)$

$48-87$

$-39$

$45-69$

$-17-42$

$-59$

$-19-46$

$-103-\left(-52\right)$

$-51$

$-105-\left(-68\right)$

$-45-\left(54\right)$

9

$-58-\left(-67\right)$

$8-3-7$

$-2$

$9-6-5$

$-5-4+7$

$-2$

$-3-8+4$

$-14-\left(-27\right)+9$

22

$64+\left(-17\right)-9$

$\left(2-7\right)-\left(3-8\right)\left(2\right)$

0

$\left(1-8\right)-\left(2-9\right)$

$\text{−}\left(6-8\right)-\left(2-4\right)$

4

$\text{−}\left(4-5\right)-\left(7-8\right)$

$25-\left[10-\left(3-12\right)\right]$

6

$32-\left[5-\left(15-20\right)\right]$

$6.3-4.3-7.2$

$-8$

$5.7-8.2-4.9$

${5}^{2}-{6}^{2}$

$-11$

${6}^{2}-{7}^{2}$

## Everyday math

Elevation The highest elevation in the United States is Mount McKinley, Alaska, at 20,320 feet above sea level. The lowest elevation is Death Valley, California, at 282 feet below sea level.

Use integers to write the elevation of:

Mount McKinley.
Death Valley.

20,329 $-282$

Extreme temperatures The highest recorded temperature on Earth was $58\text{°}$ Celsius, recorded in the Sahara Desert in 1922. The lowest recorded temperature was $90\text{°}\phantom{\rule{0.2em}{0ex}}\text{below}\phantom{\rule{0.2em}{0ex}}0\text{°}$ Celsius, recorded in Antarctica in 1983.

Use integers to write the:

1. highest recorded temperature.
2. lowest recorded temperature.

State budgets In June, 2011, the state of Pennsylvania estimated it would have a budget surplus of $540 million. That same month, Texas estimated it would have a budget deficit of$27 billion.

Use integers to write the budget of:

Pennsylvania.
Texas.

$540 million $\text{−}27$ billion College enrollments Across the United States, community college enrollment grew by 1,400,000 students from Fall 2007 to Fall 2010. In California, community college enrollment declined by 110,171 students from Fall 2009 to Fall 2010. Use integers to write the change in enrollment: 1. in the U.S. from Fall 2007 to Fall 2010. 2. in California from Fall 2009 to Fall 2010. Stock Market The week of September 15, 2008 was one of the most volatile weeks ever for the US stock market. The closing numbers of the Dow Jones Industrial Average each day were:  Monday $-504$ Tuesday $+142$ Wednesday $-449$ Thursday $+410$ Friday $+369$ What was the overall change for the week? Was it positive or negative? $-32$ Stock Market During the week of June 22, 2009, the closing numbers of the Dow Jones Industrial Average each day were:  Monday $-201$ Tuesday $-16$ Wednesday $-23$ Thursday $+172$ Friday $-34$ What was the overall change for the week? Was it positive or negative? ## Writing exercises Give an example of a negative number from your life experience. Answers may vary What are the three uses of the $\text{“}-\text{”}$ sign in algebra? Explain how they differ. Explain why the sum of $-8$ and 2 is negative, but the sum of 8 and $-2$ is positive. Answers may vary Give an example from your life experience of adding two negative numbers. ## Self check After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section. What does this checklist tell you about your mastery of this section? What steps will you take to improve? #### Questions & Answers Equation in the form of a pending point y+2=1/6(×-4) Jose Reply definition of quadratic formula Ahmed Reply From Google: The quadratic formula, , is used in algebra to solve quadratic equations (polynomial equations of the second degree). The general form of a quadratic equation is , where x represents a variable, and a, b, and c are constants, with . A quadratic equation has two solutions, called roots. Melissa what is the answer of w-2.6=7.55 What Reply 10.15 Michael w = 10.15 You add 2.6 to both sides and then solve for w (-2.6 zeros out on the left and leaves you with w= 7.55 + 2.6) Korin Nataly is considering two job offers. The first job would pay her$83,000 per year. The second would pay her $66,500 plus 15% of her total sales. What would her total sales need to be for her salary on the second offer be higher than the first? Mckenzie Reply x >$110,000
bruce
greater than $110,000 Michael Estelle is making 30 pounds of fruit salad from strawberries and blueberries. Strawberries cost$1.80 per pound, and blueberries cost $4.50 per pound. If Estelle wants the fruit salad to cost her$2.52 per pound, how many pounds of each berry should she use?
$1.38 worth of strawberries +$1.14 worth of blueberries which= $2.52 Leitha how Zaione is it right😊 Leitha lol maybe Robinson 8 pound of blueberries and 22 pounds of strawberries Melissa 8 pounds x 4.5 = 36 22 pounds x 1.80 = 39.60 36 + 39.60 = 75.60 75.60 / 30 = average 2.52 per pound Melissa 8 pounds x 4.5 equal 36 22 pounds x 1.80 equal 39.60 36 + 39.60 equal 75.60 75.60 / 30 equal average 2.52 per pound Melissa hmmmm...... ? Robinson 8 pounds x 4.5 = 36 22 pounds x 1.80 = 39.60 36 + 39.60 = 75.60 75.60 / 30 = average 2.52 per pound Melissa The question asks how many pounds of each in order for her to have an average cost of$2.52. She needs 30 lb in all so 30 pounds times $2.52 equals$75.60. that's how much money she is spending on the fruit. That means she would need 8 pounds of blueberries and 22 lbs of strawberries to equal 75.60
Melissa
good
Robinson
👍
Leitha
thanks Melissa.
Leitha
nawal let's do another😊
Leitha
we can't use emojis...I see now
Leitha
Sorry for the multi post. My phone glitches.
Melissa
Vina has $4.70 in quarters, dimes and nickels in her purse. She has eight more dimes than quarters and six more nickels than quarters. How many of each coin does she have? Mckenzie Reply 10 quarters 16 dimes 12 nickels Leitha A private jet can fly 1,210 miles against a 25 mph headwind in the same amount of time it can fly 1,694 miles with a 25 mph tailwind. Find the speed of the jet. Crispy Reply wtf. is a tail wind or headwind? Robert 48 miles per hour with headwind and 68 miles per hour with tailwind Leitha average speed is 58 mph Leitha Into the wind (headwind), 125 mph; with wind (tailwind), 175 mph. Use time (t) = distance (d) ÷ rate (r). since t is equal both problems, then 1210/(x-25) = 1694/(×+25). solve for x gives x=150. bruce the jet will fly 9.68 hours to cover either distance bruce Riley is planning to plant a lawn in his yard. He will need 9 pounds of grass seed. He wants to mix Bermuda seed that costs$4.80 per pound with Fescue seed that costs $3.50 per pound. How much of each seed should he buy so that the overall cost will be$4.02 per pound?
33.336
Robinson
Amber wants to put tiles on the backsplash of her kitchen counters. She will need 36 square feet of tiles. She will use basic tiles that cost $8 per square foot and decorator tiles that cost$20 per square foot. How many square feet of each tile should she use so that the overall cost of the backsplash will be $10 per square foot? Imaan Reply Ivan has$8.75 in nickels and quarters in his desk drawer. The number of nickels is twice the number of quarters. How many coins of each type does he have?
2q=n ((2q).05) + ((q).25) = 8.75 .1q + .25q = 8.75 .35q = 8.75 q = 25 quarters 2(q) 2 (25) = 50 nickles Answer check 25 x .25 = 6.25 50 x .05 = 2.50 6.25 + 2.50 = 8.75
Melissa
John has $175 in$5 and $10 bills in his drawer. The number of$5 bills is three times the number of $10 bills. How many of each are in the drawer? mikayla Reply 7-$10 21-$5 Robert Enrique borrowed$23,500 to buy a car. He pays his uncle 2% interest on the $4,500 he borrowed from him, and he pays the bank 11.5% interest on the rest. What average interest rate does he pay on the total$23,500? (Round your answer to the nearest tenth of a percent.)
Two sisters like to compete on their bike rides. Tamara can go 4 mph faster than her sister, Samantha. If it takes Samantha 1 hour longer than Tamara to go 80 miles, how fast can Samantha ride her bike?
8mph
michele
16mph
Robert
3.8 mph
Ped
16 goes into 80 5times while 20 goes into 80 4times and is 4mph faster
Robert
what is the answer for this 3×9+28÷4-8
315
lashonna
how do you do xsquard+7x+10=0
What
(x + 2)(x + 5), then set each factor to zero and solve for x. so, x = -2 and x = -5.
bruce
I skipped it
What
In 10 years, the population of Detroit fell from 950,000 to about 712,500. Find the percent decrease.
how do i set this up
Jenise
25%
Melissa
25 percent
Muzamil
950,000 - 712,500 = 237,500. 237,500 / 950,000 = .25 = 25%
Melissa
I've tried several times it won't let me post the breakdown of how you get 25%.
Melissa
Subtract one from the other to get the difference. Then take that difference and divided by 950000 and you will get .25 aka 25%
Melissa
Finally 👍
Melissa
one way is to set as ratio: 100%/950000 = x% / 712500, which yields that 712500 is 75% of the initial 950000. therefore, the decrease is 25%.
bruce
twenty five percent...
Jeorge
thanks melissa
Jeorge
950000-713500 *100 and then divide by 950000 = 25
Muzamil