Writing Expressions

We need to translate words in

mathematical symbols. Here are some

words you should know.Operation Verbal Phrase Expression

Addition: sum, plus, total, more than, increased by.

The sum of 2 and a number x

2+x

A number n plus 7 n+7

Subtraction: difference, less than, minus, decreased by.

The difference of a number n and 6

n-6

A number y minus 5 y-5

Multiplication: times, product, multiplied by, of.

12 times a number y

12y

1/3 of a number x 1/3(x)

Division: Quotient, divided by, divided into.

The quotient of a number k and 2

k/2

Translate these verbal phrases into

expressions…• 4 Less than the quantity 6 times a

number n.

• 3 times the sum of 7 and a number y.

• The difference of 22 and the square of a number m.

• The quotient when the quantity 10 plus a number x is divided by 2

Let’s try it with a word problem…

• A piece of ribbon L feet long is cut from a ribbon 8 feet long. Write an expression for the length (in feet) of the remaining piece.

Let’s try another…

• You work with 5 other people at an ice cream stand. All the worker put their tips into a jar and share the amount in the jar equally a the end of the day. Write an expression for each person’s share (in dollars) for the tips.

Let’s Talk About Rate

Here’s some vocab…

• Rate• Is a fraction that compares 2 quantities

measured in different units.

• Unit Rate• When the denominator of the fraction is

1 unit.

Here’s an example of a problem involving

rate…

€

110mi

2hrs=110 ÷ 2

2 ÷ 2=55mi

1hr

A car travels 110 miles in 2 hours. Find the unit rate.

The unit rate is 55 miles per hour, or 55mi/h, or 55mph

Here’s one for you to try…

• Your basic monthly charge for cell phone service is $30, which includes 300 free minutes. You pay a fee for each extra minute you use. One month you paid $3.75 for 15 extra minutes. Find your total bill if you use 22 extra minutes.