7th Grade Unit 1A Review

Which of the following statements BEST describes a situation in which opposite quantities combine to make zero?

• Pepper baked 12 cookies, and put each cookie in an individual bag.

   

• Lola received $20 from her grandma and another $20 from her grandpa.

• A climber ascended 100 feet and then descended 100 feet.

• Bronson loses his wallet, which contained $50.

Answer explanation

Ascending 100 feet would put you at a positive 100 feet elevation. Descending 100 feet (-100) would bring you back down to 0.

100 + -100 =0

Tags

CCSS.7.NS.A.1A

What is the sum of –7.2 + 9.9 + –4.5?

• –21.6

• –1.8

• 1.8

• 21.6

Answer explanation

-7.2 + 9.9 = 2.7

2.7 + (-4.5)= -1.8

Tags

CCSS.7.NS.A.1C

At 4:00 a.m., the temperature outside was 12°F below zero. By noon, it rose by 15°F.  At 6:00 p.m., the temperature dropped by 7°F. What was the evening temperature?

• –34°F

• -4°F

• 10°F

• 34°F

Answer explanation

12F below zero is -12F. Since the temperature rose 15F, we would add -12+ 15 to get 3F. Then, since the temperature dropped 7F, we would add

3F+(-7F) to get -4F.

Tags

CCSS.7.NS.A.3

Lindsay is competing on Jeopardy. She begins with an initial score of 150 points but loses 500 points throughout the game. She represents her score using the expression shown?

150 – 500

Which of the following expressions also represents Lindsay’s Jeopardy score?

• 500 – (–150)

• 150 + 500

• 150 + (–500)

• –500 – 150

Answer explanation

We can change 150 - 500 into an addition problem by adding the additive inverse.

So 150 - 500 would be

150 + (-500)

They would also yield the same answer.

Tags

CCSS.7.NS.A.1B

Lola owes Andy $2, and Andy owes Lola $5. Which of the following statements means the same thing?

• Lola owes Andy $3.

• Lola owes Andy $7.

• Andy owes Lola $3.

• Andy owes Lola $7.

Answer explanation

Lola owes Andy $2, but since Andy also owes Lola $5, we can set this up as

-5 + 2 = -3, meaning Andy still owes Lola 3 dollars.

Tags

CCSS.7.NS.A.1C

Mari had $237.60 in her checking account at the beginning of the week. Over the next three days, she withdrew $5.50 on Monday, deposited $20.67 on Tuesday, and withdrew $100.25 on Wednesday. How much money was in her bank account at the end of Wednesday?

Answer explanation

Withdraw means taking money out of her account, so it would be represented as a negative number. Deposit mean putting money into the account, so it would be represented as a positive number. Your equation is:

$237.60 + (-$5.50) + $20.67 + (-$100.25)

Answer: $152.52

Tags

CCSS.7.NS.A.3

• 1

• 1

Answer explanation

-4/5 and 4/5 are additive inverses, so when you sum them up, they equal zero.

Tags

CCSS.7.NS.A.1B

Answer explanation

-8.1

First we have to change the equation into an addition problem using additive inverse.

5 2/9 + (-8.1) + (-5 2/9)

Then you can use communitive property to simplify.

5 2/9 + (-5 2/9) + (-8.1)

5 2/9 + (-5 2/9) = 0, so 0 + (-8.1)= -8.1

Tags

CCSS.7.NS.A.1D

Answer explanation

We can use communitive and the associative property to simplify:

-1/2 + 1/2 + 7 + 3

0 + 7 + 3 = 10

Tags

CCSS.7.NS.A.3

Which point on the number line represents 2 more than 5? How do you know?

• A

• B

• C

• D

Answer explanation

2 more than 5 is 5 + 2, which is 7.

Tags

CCSS.1.NBT.C.4

CCSS.2.MD.B.6