Writing Equations & ExpressionsNotes - 9/17/2012

Our Organizer

As we go through our notes, pick out any words that might key you into using a specific operation!

Example: SUMWrite “sum” in addition section.

Vocabulary

Algebraic Expressions and Equations

Variable: any letter that represents an unknown number.The number of students in class minus 2.S = Number of students

Expression: 4x + 2A mathematical phrase that only contains numbers,

variable, and operations.

Equation: 4x + 2 = 10 + xA mathematical statement that shows to phrases are

equal.

+, - , ,

• Translating sentences into equations.

Ex 1) Five times the number a squared is three times the sum of b and c.

a the sum ofFive times squared is three times b and c5 ∙ 𝑎2 = 3 ∙ (b + c)

Simplify…5 = 3(b+c)

Practice

Twenty-seven times k is h squared decreased by 9.

27k = - 9

Practice

• The difference of a number and twenty-five is two.

K - 25 = 2

1. Three times the difference between eighteen and thirteen

2. Five less than the product of eight and three

3. Twelve minus the product of nine and seven

4. The difference between sixteen, and the product of seven and two

5. Ten more than the quotient of thirty-six divided by nine

6. Twice as much as the sum of eighteen and eleven

7. Twenty-four less than the product of six and seven

8. Thirty-seven more than the quotient of twenty-four divided by eight

3 (18 - 13)

(18

12 -

36

(6

16 – 7

2 (18 + 11)

37 +

Practice

Suppose an adult bottlenose dolphin weighs 800 pounds. This is 735 pounds more than a typical newborn bottlenose dolphin. Which equation could be used to find the weight of a typical newborn bottlenose dolphin?

A) X – 735 = 800B) X + 735 = 800C) X – 800 = 735D) X + 800 = 735

The big picture…

3 x (4 + 1)

When you see this expression, you should be able to understand that having "3 x" in front of the parentheses means that the value of the expression will be three times as big as 4 +1 would be by itself.

The big picture…

35 - (2 x 4)

When you see this expression, you should be able to understand that having x 4 after the 2 means that you will be subtracting four times as much as you would for 2 by itself.

Add

• Plus• Sum• Total• More than• Increased by

Subtract

• Minus• Less*• Difference*• Less than*• Decreased by• Subtracted from*

Multiply

• Times• Product• Multiplied• Of• Twice (x2)• Triple (x3)

Divide

• Divided• Quotient

Equals

• Is equal to• Is• Is the same as• Is identical to• Is as much as

Exit Slip

The equation for the volume of a cylinder is =

The equation for the volume of a cone is =

Describe the relationship between the volumes of these two shapes if they have equal bases and heights.