ALGEBRA VARIABLES AND EXPRESSIONS Algebra Uses symbols to

ALGEBRA

VARIABLES AND EXPRESSIONS • Algebra – Uses symbols to represent quantities that are unknown or that vary. You can represent mathematical phrases and realworld relationships using symbols and operations. • Quantity – Anything that can be measured or counted. • Variable – a symbol usually a letter that represents a value.

VARIABLE AND EXPRESSION • Numerical Expression – a mathematical phrase involving numbers and operations symbols, but no variables. – Example: 1+4=5

VARIABLE AND EXPRESSION • Algebraic expression – When variables are combined with symbols. – Example x+5 The expression x + 5 equals different values.

Operation + - Word Phrases • • • A number plus 5 Add 5 to a number Sum of a number and 5 5 more than a number A number increased by 5 A number minus 11 Subtract 11 from a number Difference of a number and 11 11 less than a number A number decreased by 11 X less a number 11 × 3 times a number 3 multiplied by a number Product of 3 and a number ÷ A number divided by 7 7 divided into a number Quotient of a number and 7 Expression N+5 X - 11 3 m

EXAMPLE 1 – WRITING EXPRESSIONS WITH ADDITION AND SUBTRACTION • What is an algebraic expression for the word phrase? § 32 more than a number n § 58 less a number n

EXAMPLE 2 – WRITING EXPRESSIONS WITH MULTIPLICATION AND DIVISION • What is an algebraic expression for the word phrase? a) 8 times a number n b) The quotient of a number n and 5

EXAMPLE 3 – WRITING EXPRESSIONS WITH TWO OPERATIONS • What is an algebraic expression for the word phrase? a) 3 more than twice a number x b) 9 less than the quotient of 6 and a number x c) The product of 4 and the sum of a number x and 7

EXAMPLE 4 – USING WORDS FOR AN EXPRESSION • What word phrase can you use to represent the algebraic expression 3 x ? Expression 3 x Word Phrase three times a number x or the product of 3 and a number x

EXAMPLE 5 – Writing a Rule to Describe a Pattern