Module 9 Lesson 2

Module 9 Lesson 2

By Mr. Wellner

​For this Lesson you need:

Pencil and Notebook,

No Calculator Needed​

Multiple Choice

BELL WORK:

Consider this equation:

c - 45 = 60

Which sentence describes the equation?

• 45 is less than an unknown number, which is 60.

• An unknown number less than 45 is 60

• When an unknown number is taken away from 45, the result is 60.

• 45 less than an unknown number is 60

​I CAN...

Use Addition and Subtraction Equations to Solve Problems

6th | Math

Goal

Vocabulary

Vocabulary

When you subtract the same amount to both sides of an equation and the two sides will remain equal.

Subtraction Property of Equality

When you add the same amount to both sides of an equation and the two sides will remain equal.

​Addition Property of Equality

Open Ended

Weights are shown on the scale. Each square is 1 unit, but the value of the triangle x is unknown. The scale sides are balanced.

Write an equation that represents the weights on the scale.

If each square is equal to 1 unit, and the triangle labeled x is an unknown weight then the quantity on the left equals 9 and the quantity on the right is x + 4.

​

9 units

9 = x + 4

x + 4 units

Open Ended

Weights are shown on the scale. Each square is 1 unit, but the value of the triangle x is unknown. The scale sides are balanced.

9 = x + 4

How can we remove weights from both sides and keep the scale balanced if the triangle on the right only has the triangle left?

Open Ended

Weights are shown on the scale. Each square is 1 unit, but the value of the triangle x is unknown. The scale sides are balanced.

9 - 4 = x + 4 - 4

After removing 4 blocks from each side, how many blocks remain on the left side, what is left on the right side?

9 units

9 = x + 4

9 - 4 = x + 4 - 4

5 = x​

​

The weight of the triangle is 5 units.​

x + 4 units

​Subtraction Property of Equality

You should write all of this down in your notebooks.

Fill in the Blanks

Fill in the Blanks

Open Ended

A plant is 6 inches tall. After 2 weeks, the plant is 14 inches tall. If we let x represent how many inches the plant grew in 2 weeks, what equation can we use to answer the problem?

Where 6 is how tall the plant started, x is how much it grew, and 14 is how tall it was after 2 weeks.

​

Think: What can we do to solve for x (how much did the plant grow in 2 weeks?)

6 + x = 14

Fill in the Blanks

Subtraction Property of Equality

6 + x = 14

6 - 6 + x = 14 - 6

x = 8​

​

​

You should write all of this down in your notebooks.

Multiple Choice

Sara had $8.50 in her pocket. She earned m dollars babysitting and now she has $20.25. How much did she earn babysitting? What equation should we use to solve this problem?

• $8.50 + $20.25 = m

• $8.50 - m = $20.25

• $8.50 + m = $20.25

• $20.25 + m = $8.50

We subtract 8.50 from both sides to get m by itself.

​

Sara made $11.75 babysitting.​

8.50 -8.50 + m = 20.25 - 8.50

m = $11.75​

$8.50 + m = $20.25

Sara had $8.50 in her pocket. She earned m dollars babysitting and now she has $20.25. How much did she earn babysitting?

Explanation

Multiple Choice

How would we solve x - 7 = 12?

• Subtract 12 from both sides

• Add 12 to both sides

• Subtract 7 from both sides

• Add 7 to both sides

x - 7 = 12

YES! We would add 7 to both sides.

x - 7 + 7 ​= 12 + 7 This is the Addition Property of Equality.

x = 19​

6th | Math

Addition Property of Equality

Let's check your understanding.

4 Questions

​- Mr. Wellner

" If there is time left over, do your homework."