Unit 2 Test Numbers & Operations

Todd's team starts a football game. On the first play, they gain 6 yards. On the second play, they lose 12 yards. The expression 6+(-12) represents this situation.

What was the total yardage that was gained or lost?

Hint: Solve the equation of 6 + (-12). If it is a positive number, they gained and negative number lost.

• 6 yards gained

• -6 yards lost

• 8 yards gained

• -8 yards lost

Answer explanation

6 + (-12) means that you are taking 6 - 12. If you look at this on a number line, starting from +6 you will go left 12 as it is a negative number. The end result is -6.

What is the sum of -18 and -27?

Hint: What does sum mean you do with the equation.

• -45

• -9

• 9

• 45

Answer explanation

-18-27 means that your number will remain a negative for the solution. Add the two numbers together and you get 45.

Peyton says the sum of two numbers can never be zero. Explain why Peyton's reasoning is incorrect.

• The sum of two numbers can be zero if one number is the additive inverse of the other.
• The sum of two numbers can be zero if one number is even and the other is odd.
• The sum of two numbers can be zero if one number is positive and the other is negative.
• The sum of two numbers can be zero if both numbers are zero.

Answer explanation

Additive inverse is basically considering the opposite. If you were to have a positive 7 and a negative 7, that would equal to zero.

7 - 7 = 0

Think of it as you had 7 cookies, you ate those 7 cookies, you were then left with 0 cookies.

In lesson 8-4, problem 10 asked that you create a word problem that you can solve by adding a positive and a negative number. You are to write an example of a word problem using a positive and negative number.

Below is an example, you cannot use this.

Alvii went trick-o-treating and got 45 candy bars. She then consumes 32 of those candy bars. How many bars are left for sharing?

It is taking the positive number, negative number and creating an equation to solve.

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Answer explanation

You can create any word problem as long as it is using a positive and negative number. It doesn't have to be overly complicated.

Which value of x makes the following statement true?

1.4 - x = a positive number

• x = 1.6

• x = 2.4

• x = -1.4

• x = 1.4

Answer explanation

If you plug in -1.4 into the equation, you get

1.4 - (-1.4) =

If you recall that subtracting a negative number means that you add.

1.4 + 1.4 = 2.8

That gives the answer as a positive statement.

A fish is 12.4 m below the surface of the ocean. The fish swims down 3.2 m. Then it swims up 9.8 m. What is the fish's new position relative to the surface of the ocean?

• -1.4 m

• 6.6 m

• 15.8 m

• -5.8 m

Answer explanation

Looking at it in equation form

-12.4 - 3.2 + 9.8

The fish started at 12.4, going down or left on a number line is considered negative, going up or to the right is considered positive.

Decide if the sum of each expression is positive. Solve the equation to help determine if needed.

There are two choices.

• -34 + 89

• 5.5 + (-5.4)

• 405 + (-405) + (-3.9)

• 4 5/8 + (-5 1/8)

Decide if the sum of each expression is negative. Solve if you need to check.

There are two choices.

• 4 5/8 + (-5 1/8)

• 5.5 + (-5 4/10)

• -34 + 89

• 405 + (-405) + (-3.9)

Which situation could the expression (-6) -3 represent?

• Take a screen break, stand up, do 3 jumping jacks, give a high five and then sit down.

  You get extra points!

• Dina spent 6 dollars on a McChicken Combo. Then she spent 3 dollars on a McFlurry.

• Elijah dropped an anchor 6 meters into the lake. Then he raised it 3 meters.

• Dora had a pack of 6 pencils. Then she gave 3 pencils away.

Answer explanation

As the expression is focused subtracting or taking away the number, you need to have an example that would represent the loss of the numbers.

When you have two negative numbers, do you add or subtract the expression?

• Addition

• Subtraction

Answer explanation

If you are looking at two negative numbers in an expression, you will have to add the two numbers together and your answer remains negative.