1. PRE-ALGEBRA

2. Variables and Expressions (1-1) numerical expression: a mathematical phrase (number sentence) that contains only numbers and operation symbols variable - a letter that stands for a number Example: x = 4n = 35 algebraic expression - a number sentence that uses numbers, at least one operation [+, -, x, /], and at least one variable Example: 5 x = 20 n  5 = 7 To translate words an algebraic expression, you need to use operation clues to tell you what to do with the numbers “Add”itionSubtractMultiplication Division sumdifferencemultiplydivide plusminustimes more thanless thanof increased bydecreased byproductquotient togetheraparteach -------------> “ “ equal groups ---> “ “ What is a “numerical expression”? What is a “variable”? What is an “algebraic expression”? How do you translate words into an algebraic expression?

3. PRE-ALGEBRA Variables and Expressions (1-1) Words -----------------> Algebraic Expression nine more than a number-----------------> y + 9 4 less than a number -----------------> n - 4 a number times 3-----------------> z x 3; z 3; 3z a number divided by 12 -----------------> k divided 12; k / 12 5 times the quantity (amount) ----------------->5 x (4+c); 5 (4+c); 5(4+c) of 4 plus a number Example: Emily has twice as many cards as Jose. Then, she buys four more cards for $2 each. Write an algebraic expression for the total amount of cards Emily has. info not needed -----------------> the cost of each card unknown info -----------------> how many card Jose has operations-----------------> “twice” = times two “buys four more” = plus 4 Words: Emily’s Cards = twice Jose’s cards plus 4Write the equation in words first J = number of cards Jose has define any unknown quantities E = number of cards Emily’s hasas a letter (variable) Equation: E = 2 J + 4 or E = 2J + 4

4. PRE-ALGEBRA Identify each expression as a numerical expression or an algebraic expression. For an algebraic expression, name the variable. numerical expression Algebraic expression; t is the variable. a. 7  3 b. 4t Variables and Expressions LESSON 1-1 Additional Examples

5. PRE-ALGEBRA Write an algebraic expression for the cost of p pens priced at 29¢ each. = number of pens. Words times Let 29¢ number of pens p The algebraic expression 29 p, or 29p, describes the cost of p pens. Expression29 p Variables and Expressions LESSON 1-1 Additional Examples

6. PRE-ALGEBRA 1.the total of h and 56 2.three less than d 3.5 decreased by three4.a divided by 7 5 – 3; numeric h + 56; algebraicd – 3; algebraic a ÷ 7; algebraic Write an expression for each word phrase. Then identify each expression as a numeric or an algebraic expression. Variables and Expressions LESSON 1-1 Lesson Quiz