Solve a wide range of mathematical problems that include: number operations/number sense, measurement, geometry, data analysis (including charts, tables, graphs), statistics, and probability
Strategy – Use Multiple Steps to Solve Problems
To successfully apply skills in mathematics, a student must be a good problem solver. Problem solving is a multi-step operation. To solve math word problems, students must:
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Read the problem carefully, paying attention to detail
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Define the type of answer that is required and eliminate extraneous information
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Identify key words that will assist them in choosing the correct operation or in the case of multi-step problems, the correct operations
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Use a graphic organizer
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Set up the problem correctly and remember the order of operations
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Use mental math and estimation skills
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Check the answer for reasonableness
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Use a calculator accurately and always double-check the answers
The following information can be used to help students understand the problem solving process and gain confidence in their own ability to solve math problems.
Read the Problem Carefully
The first mistake students make when trying to solve a problem is to not read carefully. They breeze through the problem and think they know what the problem is asking them to do. Unfortunately, they usually decide the wrong thing. Reading comprehension skills are very important in math. The following graphic organizer can help students focus their attention on what the problem is really asking them to do. Have students use the organizer on different types of problems. As they become more comfortable with the process, they will no longer need the organizer but rather will think through the process in a logical manner. The graphic organizer forces students to look at the details of the problems and also helps them work through the information in an organized way.
Define the Answer that is Needed
One of the most difficult tasks for students is to determine what the question is asking them to do. Students should start by asking themselves: “What is the exact question I need to answer?” The second step is to see what information is provided and what the student needs to know in order to answer the question. Step three is to eliminate all the extraneous information that is included in the problem.
Look at the following example.
Harry Potter has asked his friend Hermione for a potion to turn them and their friend Ron into birds. They need to make a trip to Diagon Alley as birds because the flying car is in for repairs.
Diagon Alley is 9 miles away and a dose of the potion lasts 50 minutes. They only have enough potion for one dose each. If they can go 24 miles an hour as birds, and they start at 4:30 p.m. , can they get to Diagon Alley and back to Hogwarts again before the potion runs out at 5:20 p.m.? If so, how much time will they be able to spend in the Alley?
The next thing is to figure out what information you already have and what you need to know to answer the question(s).
Information you know.
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As birds, Harry and Ron can travel 24 miles in one hour.
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They want to go 9 miles twice in 50 minutes.
What information is not needed?
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They can leave at 4:30 p.m.
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They must return at 5:20 p.m.
What is the problem asking?
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Can Harry and Ron get to Diagon Alley and back in 50 minutes?
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How long can they stay in Diagon Alley
How will you need to express your answer?
In this case, the question that has to be answered is how much time they will be able to spend in the alley. Since it is a time question, the answer will need to be expressed in hours or minutes. Following these simple and organized steps, students can clearly identify the question they need to answer in any problem and eliminate extraneous information that can often result in a wrong answer.
Problem adapted from Ask Dr. Math: FAQ, Word Problems. Retrieved from the World Wide Web on February 4, 2006 at: http://www.mathforum.org/dr.math/faq/faw.word.problems.html.
Strategy – Identify Key Words
Math has its own unique vocabulary. Help students expand their vocabulary by dissecting word problems and finding key words or by having students build their own personal math dictionary. They can list key words, write the definition in their own words, and provide an example. This type of dictionary can grow with the students as they venture into higher levels of math. An example of a personal dictionary would be:
My Personal Dictionary
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Math Term
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Definition (In your own words)
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Your Own Example
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Example: Variable
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A letter that stands for a number in an equation. It is a variable because its value can change.
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6n x 2
n is the variable
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Types of Math Vocabulary Words’
The following is a list of commonly used math terms that will be helpful to students as they work with word problems.
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Common Words that Indicate Math Operations
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Addition
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Subtraction
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Multiplication
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Division
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Equals
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Increased by
More than
Combined
Together
Total of
Sum
Added to
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Decreased by
Minus
Less
Difference
Between/of
Less than
Fewer than
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Times
Multiplied by
Product of
Increased/decreased by a factor of (this is both addition/ subtraction and multiplication)
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Of (as in half of)
Times
Multiplied by
Product of
Increased or decreased by a factor of (this is both addition/ subtraction and multiplication)
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Is, are
Was
Were
Will be
Gives
Yields
Sold for
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Basic Geometry Vocabulary Words
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Acute
Angle
Area
Center
Chord
Circumference
Complementary
Congruent
Cube
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Cube
Cylinder
Degree
Equilateral
Geometric
Height
Hexagon
Intersect
Isosceles
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Length
Obtuse
Parallel
Pentagon
Perimeter
Perpendicular
Plane
Plot
Polygon
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Pyramid
Quadrilateral
Radius
Rectangle
Rhombus
Segment
Scalene
Sphere
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Supplementary
Symmetrical
Triangle
Trapezoid
Vertex
Volume
Width
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Selected Mathematic Vocabulary Words
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Absolute value
Approximately
Base
Commutative property
Comparison
Complex
Convert
Determine
Diagram
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Distributive property
Equality
Error of measurement
Exponent
Expression
Face value
Finite
Formula
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Frequency
Generalization
Graph
Gross
Imply
Inequality
Inference
Interest rate
Irrational Number
Linear
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Metric system
Midpoint
Mixed number
Multiplier
Notation
Ordered pair
Percentage
Percentiles
Permutation
Probability
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Quadrant
Ratio
Rational number
Scientific notation
Simplify
Slope
Square root
Tally
Underestimate
Venn diagram
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Strategy – Geometry Concentration
One way to assist students with using and applying vocabulary is to create games such as concentration, jeopardy, or matching activities. The following is an example of a geometry matching activity. You may wish to include additional terms.
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Term
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Definition
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Right angle
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A 90 degree angle.
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Equilateral triangle
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A triangle with all sides equal.
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Scalene triangle
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A triangle having three unequal sides and angles.
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Vertex
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The intersection of two sides.
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Right triangle
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A triangle with one internal angle equal to 90 degrees.
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Pentagon
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A polygon with 5 sides and 5 angles.
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Square
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A rectangle having all four sides of equal length.
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Intersecting lines
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Lines that cross each other.
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Perpendicular lines
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Two lines that cross each other to form a 90 degree angle.
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Acute angle
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An angle less than 90 degrees.
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Chord
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The line segment between two points on a given curve.
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Radius
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A straight line extending from the center of a circle to the surface.
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Line segment
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One part of a line.
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Line
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A continuous extent of length.
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Point
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A position in space.
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Rectangle
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A quadrilateral with opposite sides parallel.
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Circle
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A closed plane.
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Hexagon
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A six-sided figure.
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Obtuse angle
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An angle greater than 90 degrees.
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Congruent angles
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Two angles that have the same measure.
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Bisect
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To separate an angle into two congruent angles.
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Degrees
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The unit that angles are measured.
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Isosceles triangle
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A triangle with at least two sides congruent.
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Similar
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Figures that have the same shape, but not necessarily the same size.
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Parallelogram
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A quadrilateral with both pairs of opposite sides parallel.
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Trapezoid
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A quadrilateral with exactly one pair of opposite sides parallel.
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The chart below gives you some of the terms that appear in many word problems. Use them in order to translate or “set-up” word problems into equations.
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English
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Math
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Example
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Translation
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What, a number
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x, n, etc.
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Three more than a number is 8.
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N + 3 = 8
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Equals, is, was, has, costs
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=
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Danny is 16 years old.
A CD costs 15 dollars.
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d = 16
c = 15
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Is greater than
Is less than
At least, minimum
At most, maximum
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>
<
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Jenny has more money than Ben.
Ashley’s age is less than Nick’s.
There are at least 30 questions on the test.
Sam can invite a maximum of 15 people to his party.
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j > b
a < n
t 30
s 15
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More, more than, greater, than, added to, total, sum, increased by, together
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+
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Kecia has 2 more video games than John.
Kecia and John have a total of 11 video games.
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k = j + 2
k + j = 11
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Less than, smaller than, decreased by, difference, fewer
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Jason has 3 fewer CDs than Carson.
The difference between Jenny’s and Ben’s savings is $75.
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j = c – 3
j – b = 75
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Of, times, product of, twice, double, triple, half of, quarter of
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x
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Emma has twice as many books as Justin.
Justin has half as many books as Emma.
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e = 2 x j
or
e = 2j
j = c x ½
or
j = e/2
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Divided by, per, for, out of, ratio of __ to __
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Sophia has $1 for every $2 Daniel has.
The ratio of Daniel’s savings to Sophia’s savings is 2 to 1.
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s = d 2
or
s = d/2
d/s = 2/1
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Example 1
Jennifer has 10 fewer DVDs than Brad.
Step 1: j (has) = b (fewer) – 10
Remember, the word “has” is an equal sign and the word “fewer” is a minus sign, so:
Step 2: j = b – 10
Example 2
Clay got 10 fewer votes than Kimberly. Reuben got three times as many votes as Clay. The three contestants received a total of 90 votes. Write an equation in one variable that can be used to solve for the number of votes Kimberly received.
Step 1: Pick which unknown will be represented by the variable. Since you’re solving for Kimberly, let k be the number of votes Kimberly received.
Step 2: Represent the other two unknowns in terms of k. Clay got 10 fewer votes so it’s k - 10 and Reuben got three times that so it’s 3(k - 10).
Step 3: Set up the equation using all of the expressions to equal 90.
k + (k - 10) + 3(k - 10) = 90
Example 3
A school is having a special event to honor successful alumni. The event will cost $500, plus an additional $85 for each alum who is honored. Write an equation that best represents the number of alumni that can be honored.
Step 1: The amount the school can spend is equal to or less than $1,000, so it’s 1,000.
Step 2: The event has a fixed cost of $500 and a variable of $85 per alum so it’s 500 + 85a.
Step 3: The equation then becomes 500 + 85a 1,000.
Example 4
A computer repair company charges $50 for a service call plus $25 for each hour of work. Write an equation that represents the relationship between the bill, b, for a service call, and the number of hours spent on the call, h.
Step 1: Some questions include a situation where there is more than one cost. One of them is fixed and one is variable. First identify the sum of the fixed and variable costs so b equals the total.
Step 2: Next, identify the fixed cost of 50 and the variable cost of 25h (25 x the number of hours).
Step 3: The equation then becomes 50 + 25h = b.
Strategy – Use a Graphic Organizer
Graphic organizers are commonly used in reading and writing. However, they are rarely found in mathematics. The following graphic organizer was developed by the Texas Center for Adult Literacy and Learning (TCALL) and is part of their adult education toolkit at: http://www.tcall.tamu.edu/toolkit/CONTENTS.HTM. The original organizer has been modified at the request of adult education practitioners, in order to incorporate additional elements that may assist students in the problem-solving process.
Modified Word Problem Graphic Organizer
Main Idea (in your own words)
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Question
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Draw a Picture/Graph/Table
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Pertinent Facts
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Irrelevant Information
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Relationship Sentence (no numbers)
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Equation (number sentence)
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Estimation (without computing)
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Computation
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Answer sentence
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Texas Center for Adult Literacy and Learning, The Adult Basic Education Teacher’s Toolkit,
Word Problem Graphic Organizer
Main Idea (in your own words)
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Question
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Draw a Picture/Graph/Table
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Pertinent Facts
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Irrelevant Information
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Relationship Sentence (no numbers)
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Equation (number sentence)
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Estimation (without computing)
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Computation
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Answer Sentence
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Set Up the Problem Correctly and Remember the Order of Operations
Many students have a rough idea of how to solve a problem but then fail to set it up correctly. One area that causes a lot of concern for students is the order of operations. Students often forget the correct order in which an operation should be calculated, thus ending up with the wrong number. Take a look at the problem below:
3 + 2 x 5 = ?
Many students will work from left to right. 3 + 2 = 5 and then 5 x 5 = 25.
The correct order is 2 x 5 = 10, 10 + 3 = 13
Use the mnemonic – Please Excuse My Dear Aunt Sally to help students remember the correct order of operation.
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Please – complete all operations within parentheses first
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Excuse – next take care of any exponents that may be present
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My Dear – complete all multiplication and division, working from left to right, before moving on to the last operations
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Aunt Sally – lastly, perform all addition and subtraction working from left to right and you are done.
The Casio fx 260 automatically applies the correct order of operations. Students should be aware that they may use a calculator on Part I of the GED Test, but not in Part II. On Part II, they must remember the correct order without prompting.
Use Mental Math and Estimation Skills
Students should be able to look at the answer to a problem and use their mental math or estimation skills to determine if the answer is reasonable. Estimation skills can also be used to eliminate certain answers from the multiple-choice selections. Spend time during each math period working on mental math and estimation skills. This will help students gain confidence in their math ability.
Check the Answer for Reasonableness
Students often fail to check and see if the answer they provide for a problem is reasonable. Although it only takes a few seconds to go back and determine if the answer is in the correct unit of measure (minutes, seconds, hours, pounds, ounces, etc.), students often fail to take the time to re-check their answers. Set aside some time before the end of the class period just for checking work. This will help students get in the habit of doing so. Provide problems with answers that use the wrong units and have students find the errors. Reinforce with students the importance of checking for reasonableness.
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