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August 23 rd , 2013. Ch. 1-1 Variables and Expressions. Definitions. Variable – Is a letter that stands for a number Variable Expression – Is a mathematical phrase that uses variables, numerals, and mathematical symbols. Example. How many miles can you drive on ten gallons of gas ?.
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August 23rd, 2013 Ch. 1-1 Variables and Expressions
Definitions • Variable – • Is a letter that stands for a number • Variable Expression – • Is a mathematical phrase that uses variables, numerals, and mathematical symbols
Example • How many miles can you drive on ten gallons of gas?
Example Cont… • Suppose you don’t know the number of miles, what can we do? • Use a variable! • Let m = the number of miles on 10 gallons • The variable expression for miles per gallon would therefore be m ÷ 10
Numerical Expression vs. Variable Expression • What is the difference between the above expressions? • Can you come up with an example of each?
Writing Variable Expressions • We can translate words into variable expressions
Quick Check • Bagels cost $0.50 each. Write a variable expression for the cost of b bagels. • Answer : 0.50b