What if you were at the supermarket and saw the price of a loaf of bread, but you weren't sure how many loaves you wanted to buy? How could you represent the total amount of money spent on bread? After completing this Concept, you'll be able to write an expression that is equal to this amount, regardless of the number of loaves you buy.
When someone is having trouble with algebra, they may say, “I don’t speak math!” While this may seem weird to you, it is a true statement. Math, like English, French, Spanish, or Arabic, is a second language that you must learn in order to be successful. There are verbs and nouns in math, just like in any other language. In order to understand math, you must practice the language.
A verb is a “doing” word, such as running, jumping, or driving. In mathematics, verbs are also “doing” words. A math verb is called an operation. Operations can be something you have used before, such as addition, multiplication, subtraction, or division. They can also be much more complex like an exponent or square root.
Suppose you have a job earning $8.15 per hour. What could you use to quickly find out how much money you would earn for different hours of work?
A noun is usually described as a person, place, or thing. In mathematics, nouns are called numbers and variables. A variable is a symbol, usually an English letter, written to replace an unknown or changing quantity.
What variables could be choices for the following situations?
a. the number of cars on a road
b. time in minutes of a ball bounce
c. distance from an object
Solution: There are many options, but here are a few to think about.
Write an expression for 2 more than 5 times a number.
1. What variable would you use to represent the length in yards of fabric?
2. Suppose bananas cost $0.29 each. Write an expression for the cost of buying a certain quantity of bananas.
3. Suppose your bank account charges you a $9 fee every month plus $2 for every time you use an ATM of another bank. Write an expression for the charges every month.
But the bank also charges us a fixed $9 every month, so we have to add that to the expression:
In 1 – 5, choose an appropriate variable to describe each situation.
- The number of hours you work in a week
- The distance you travel
- The height of an object over time
- The area of a square
- The number of steps you take in a minute
In 6 – 10, write an expression to describe each situation.
- You have a job earning $2000 a month
- Avocados are sold for $1.50 each
- A car travels 50 miles per hour for a certain number of hours
- Your vacation costs you $500 for the airplane ticket plus $100 per day
- Your cell phone costs $50 a month plus $0.25 for each text message
In 11 – 15, underline the math verb(s) in the sentence.
- Six times v
- Four plus y minus six
- Sixteen squared
U divided by three minus eight
- 225 raised to the 12 power