Expressions and Patterns Chapter 7 Expressions and Patterns

Lesson 2 – Order of Operations The order of operations is a set of rules to follow when more than one operation is used in an expression. Please Excuse My Dear Aunt Sally P – All operations in Parentheses are performed first E – Solve any exponents M and D – Multiplication and division at the same time from left to right A and S – Addition and subtraction at the same time from left to right

Lesson 2 – Order of Operations Example: 20 – (3 x 2) + 4² ÷ 4 Parentheses 20 – 6 + 4² ÷ 4 Exponents 20 – 6 + 16 ÷ 4 Multiplication 20 – 6 + 4 Division Addition 14 + 4 = 18 Subtraction

Lesson 3 – Numerical Expressions An expression is a number sentence that does not have an equal sign. A variable represents a number that is not known. Examples: Jan had 5 apples. She bought some more. 5 + a Divide 10 by 2, then add 7. (10 ÷ 2) + 7

Ordered Pairs A coordinate plane is a flat surface with an x and y axis. An ordered pair give you an x and y coordinate to plot a point. To plot an ordered pair: Start at the origin (0,0) Use the first number to count across the x axis. Use the second number to count up from the x axis (y) So, to plot the point (2,3), I would start at the bottom left of the grid. Then I would go across 2 and up 3.