Transcript Practice - Macomb

MODULE A - 2
DECIMALS AND
ORDER OF OPERATION
OBJECTIVES
•
At the end of this module, the student will be
able to…
 List the rules for working with decimals.
 Given a mathematical problem involving
decimals, add, subtract, multiply or divide
decimals with and without a calculator and
derive the correct answer.
 List the rules for order of operation when
performing calculations.
 Given a mathematical problem, determine the
proper order of operation for problems
containing addition, subtraction,
multiplication and division with and without a
calculator and derive the correct answer.
Decimals
THE RULES:
Addition
Subtraction
Multiplication
Division
ADDITION
• When working without a calculator
 Line up the decimals
 Round to the appropriate number of decimal
places
 Add:
43.45
43.45
10.311
+0.25
10.31
+0.25
54.011
54.01 = 54.0
 Round to the correct
number of places
PRACTICE
• 23.45 + 1.9283 =
• 765.987 + 0.38475 =
SUBTRACTION
• When working without a calculator
 Line up the decimals
 Round to the appropriate number of decimal
places
 Subtract:
198.24
198.24
- 40.015
- 40.02
158.235
158.22 = 158
PRACTICE
7.23 – 2.394
=
9253.9 – 50.301 =
MULTIPLICATION
• Multiply the numbers as if they are whole
numbers without decimals.
• Count the number of decimal places in the
original numbers.
• That total will be the number of decimal places
in the answer.
50.6 x 0.002 (4 places) =
506 x 2 = 1012 = .1012 (4 places)
PRACTICE
98.7 X 0.005 =
0.23 x 1000 =
DIVISION
Top Number
is the
Bottom Number is the
Numerator
Denominator
 Make the denominator a whole number by
moving the decimal place to the right.
 Move the decimal in the numerator to the right
by the same amount.
 Divide.
PRACTICE
0.68
6.8 (moved 1 places)
3.4
34 (moved 1 places)
-------------------------------------------------------
=
PRACTICE
1500
0.5
0.75
0.0025
TIME FOR PRACTICE
See practice assignment
Order of Operation
Three Rules
• First Rule:
• Order - Multiplication & Division from left to right
• Second Rule:
• Order - Addition & Subtraction from left to right
12 x 6 – 2 = (12 x 6) – 2
= 72 – 2
= 70
• PEMDAS - "Please Excuse My Dear Aunt Sally"
http://regentsprep.org/regents/math/orderop/Lorder.htm
Practice
• What will you do first?
 70 x 4 – 40 = ______
 850 x 2 x 30 = ______
 50 + 10 / 2 = ______
 27 + 25 / 5 = ______
 945 – 9 x 5 = ______
Order of Operation
• Third Rule:
 Simplification - Work inside outside
• Parenthesis ( )
• Brackets [ ]
• Braces { }
194 – {[20 x (9-5)] + 14} =
Clinical Example
• The Alveolar Air Equation –
pressure of O2 in the
alveoli
 PAO2 = FIO2 (PBaro – PH2O) – PACO2 [FIO2 + (1-FIO2)]
R
 PAO2 = 0.5 (760 – 47) – 40 [0.5 + (1 – 0.5 )]
0.8
 Parentheses:
PAO2 = 0.5 (713) – 40 [0.5 + (0.625)]
 Brackets:
PAO2 = 0.5(713) – 40 [1.125]
 Multiply left to right:
PAO2 = 357 – 45
 Subtract left to right:
PAO2 = 312 mm Hg
PRACTICE
• 100 – {[10 x (6 - 5)] + 25} = ______
• 1289 – {[120 x (23 – 13)] + 4} = ______
• 82 – [34 x (33 – 11)] + 76 = ______
ASSIGNMENTS
• Self-Assessment:
 Decimals
 Order of Operation
• Answers will be posted on website