Lesson 1 Day 2: Variables

and Expressions

Algebra 1 CPMrs. Mongold

Examples• Lorenzo bought a bag of peanuts that cost p

dollars and he gave the cashier a $20 bill. Write an expression for the amount of change that he will receive.

Examples• The area of a circle is the number times the

square of the radius. Write an expression to represent the area of a circle with radius r.

Examples• Each person in the united states produces about

3.5 pounds of trash each day.o Write an expression to describe the pounds of trash

produced per day by a family with m members

o Use the expression you wrote to predict how many pounds of trash are produced by a family of four each day, what about our class?

Examples• Kendra is saving to buy a new laptop. Write an

expression to represent the total amount of money she will have if she has s dollars saved and she adds d dollars per week for the next 12 weeks.

Examples• Mario has 55 mp3’s on his ipod. Write an

expression to represent the total number of mp3’s he will have after 18 months if he buys x mp3’s per month.

Examples• The yards of fabric needed to make curtains is 3

times the width of a window in inches, divided by 36. Which expression best represents the yards of fabric needed in terms of the width of the window w.

Examples• Tia owns a dog grooming business. How much

did she earn in one week if she groomed 14 small dogs at $25 each, 11 medium dogs at $27.50 each, and 3 large dogs at $36.50 each. o Write an expression using the variables s, m, and l and then evaluate.