Students review the order of operations and using formulas.

2. Nurses setting up intravenous or IV fluids must control the flow rate F, in drops per minute. Expressions and Formulas They use the formula , where V is the volume of the solution in milliliters, d is the drop factor in drops per milliliter, and t is the time in minutes. Suppose a doctor orders 1500 milliliters of IV saline to be given over 12 hours. Using the drop factor of 15 drops per milliliter, the expression gives the correct flow rate for this patient’s IV.

3. In order to find that value, you must follow the _________________. Some students remember the order by using the following mnemonic: P E M D A S lease xcuse y ear unt ally (parentheses / grouping symbols) (exponents) (multiplication – from left to right) (division – from left to right) (addition – from left to right) (subtraction – from left to right) order of operations Expressions and Formulas A numerical expression such as must have exactly one value.

4. Find the value of = [2( 6 ) 2 + 3] ÷ 5 = [2( 36 ) + 3] ÷ 5 = [ 72 + 3] ÷ 5 = [ 75 ] ÷ 5 = 15 Expressions and Formulas

5. Find the value of Expressions and Formulas

6. _________ are symbols, usually letters, used to represent unknown quantities. Variables Expressions that contain at least one variable are called algebraic expressions . You can evaluate an algebraic expression by replacing each variable with a number and then applying the order of operations. ( x – y ) 2 – 2 wz = = ( – 0.1) 2 – 12( – 3) = ( 0.01) + 36 = 36.01 Expressions and Formulas Evaluate the expression ( x – y ) 2 – 2 wz , if w = 6, x = 0.4, y = , and z = – 3. ( 0.4 – ) 2 – 2(6)( - 3 )

7. A _______ is a mathematical sentence that expresses the relationship between certain quantities. formula If you know the value of every variable in the formula except one, you can find the value of the remaining variable. This shape is called a _________. trapezoid The formula for calculating the area of a trapezoid is Expressions and Formulas 14 in 26 in 6 in

8. Find the area of the trapezoid: The area of the trapezoid is 120 square inches. Expressions and Formulas 14 in 26 in 6 in

9. Find the value of Expressions and Formulas

10. End of Lesson Expressions and Formulas