Evaluating Variable Expressions

Order of operations

100

What does "PEMDAS" stand for?

P = parentheses E = exponents M = multiplication D = division A = addition S = subtraction

200

What does 8^2 (8 to the power of 2) mean?

8 times itself, or 8*8, or 64.

300

In the expression 9 x 3 - (7 + 9), which step should we start with according to PEMDAS?

7+ 9 = 16

400

Solve: 5(4² + 3)

5(16 + 3) = 5*19 = 95

500

(3² + ( 6 / 2 + 7²)) + 4²

77

Exponents

100

What is 2²?

4

200

What is 3³?

27

300

x⁴ ; use x = 3

81

400

x(y²) ; use x = 3, y = 5

75

500

y(y ³) + x ; use x = 3, y = 2

19

Evaluate algebraic expressions

100

3(y + x) ; use x = 4, y = 0

3(4) = 12

200

4 + xy ; use x = 7 and y = 3

4 + 21 = 25

300

8(5 - x) - y ; use x = 3 and y = 12

8(5 - 3) - 12 = 8(2) - 12 = 16 - 12 = 4

400

(c + d) + 4(c) ; use c = 8, d = 9

(8 + 9) - 4(8) = 17 + 32 = 49

500

5(f - h) - 2h       use h = 3, f = 6

5(2 - -1) - 2(-1) = 5(2 + 1) + 2 = 5(3) + 2 = 9

Combining Like terms

100

4y + y

5y

200

5h + 3b + 2b

5h + 5b

300

7x + 4 -2x -6y

5x + 4 - 6y

400

8t + 4h -2t - 6 + 5h

6t + 11h - 6

500

x² + 3x² - 3b + 6x -2x²

2x²- 3b + 6x

Percents

100

John had 40 chocolate bars. He sold 20 of his chocolate bars. What percent of chocolate bars did he eat.

50%

200

Rob's paycheck was $800 but he only received $200. What percent of his paycheck did he receive?

25%

300

A stadium has 350 seats. They sold out 70% of the seats. How many seats did they sell?

245 seats

400

There are 500 students in a school. 30% of the students walk to school. How many kids walk to school?

150 students walk to school.

500

There are 500 students in a school. 30% of the students walk to school. How many kids do not walk to school?

350 students