Cheat sheet

GED Mathematical Reasoning Cheat Sheet

Quantitative: Rational Numbers

25%of exam

Number OpsFractions & DecimalsRatios & PercentsStatisticsProbability

Quantitative: Measurement

20%of exam

Area & PerimeterVolume & Surface AreaPythagorean TheoremUnit ConversionFormula Sheet

Algebraic: Equations

30%of exam

ExpressionsLinear EquationsInequalitiesQuadraticsSystems

Algebraic: Graphs & Functions

25%of exam

SlopeGraphing LinesFunctionsDomain & RangeNonlinear

Quick Facts

Exam
GED Mathematical Reasoning
Items
About 46 questions
Item types
MC, drag-drop, hot spot, fill-in
Time
115 minutes
Pass score
145 out of 200
College Ready
165 or higher
College Ready + Credit
175 or higher
Calculator
TI-30XS Multiview onscreen
No-calc items
First 5 questions only

Order of Operations

Please Excuse My Dear Aunt Sally

Parens firstExponents nextMultiply/divide left-rightAdd/subtract left-right

Mean vs Median

Mean

  • Sum ÷ count
  • Pulled by outliers

Median

  • Middle sorted value
  • Ignores outliers

Average vs middle value

Order of Operations & Signs

PEMDAS
P-E-MD-AS order
Two negatives multiplied
Positive product
Negative times positive
Negative product
Absolute value
Distance from zero
Reciprocal
Flip numerator, denominator
Keep-Change-Flip
Divide fractions method

Keep-Change-Flip

Keep first, change sign, flip second

Keep: first fractionChange: ÷ to ×Flip: second fraction

Fractions, Decimals & Percents

Fraction to decimal
Divide top by bottom
Decimal to percent
Multiply by 100
Percent to decimal
Divide by 100
Unit rate
Amount per one unit
Proportion
Equal ratios, cross multiply
Percent change
Difference over original ×100Common trap
Percent of whole
Part divided by percent
Markup
Price × (1 + rate)
Discount
Price × (1 − rate)

Percent Trap Reminder

Always divide by the original value

New minus originalDivide by originalMultiply by 100

Statistics & Probability

Mean
Sum divided by count
Median
Middle value, sorted data
Mode
Most frequent value
Range
Max minus min
Weighted average
Values times their frequencies
Probability
Favorable over total outcomes
Probability range
Between 0 and 1
Frequency table
Counts data value occurs

Formula Sheet Reminder

Formula sheet given; know when to use it

Given: all formulasMissing: when to applyPractice: word-problem cues

Area vs Circumference

Area

  • Space inside shape
  • Square units

Circumference

  • Distance around circle
  • Linear units

Inside vs around

Formula Picker

  1. Need enclosed spaceArea formula(Square units)
  2. Need distance aroundPerimeter or circumference(Linear units)
  3. Need space inside solidVolume formula(Cubic units)
  4. Need outside coveringSurface area formula(Square units)
  5. Right triangle sidePythagorean theorem(a²+b²=c²)
  6. Irregular shapeSplit into simple shapes(Add or subtract)
  7. Scaled drawing givenSet up proportion(Cross multiply)

Area Formulas

Square area
A = s²
Rectangle area
A = lw
Parallelogram area
A = bh
Triangle area
A = 1/2 bh
Trapezoid area
Half height times base sum
Circle area
A = πr²

Volume vs Surface Area

Volume

  • Space inside solid
  • Cubic units

Surface Area

  • Material covering outside
  • Square units

Fill vs cover

Perimeter & Circumference

Square perimeter
P = 4s
Rectangle perimeter
P = 2l + 2w
Triangle perimeter
Sum of three sides
Circumference (radius)
C = 2πr
Circumference (diameter)
C = πd
Composite figure area
Add or subtract shapes

Volume & Surface Area

Rectangular prism volume
V = lwh
Rectangular prism surface
SA = 2lw+2lh+2wh
Cylinder volume
V = πr²h
Cylinder surface
SA = 2πrh + 2πr²
Cone volume
V = 1/3 πr²h
Sphere volume
V = 4/3 πr³
Sphere surface
SA = 4πr²

Pythagorean, Scale & Units

Pythagorean theorem
a² + b² = c²Right triangles only
Hypotenuse
Longest side, right triangle
Scale factor use
Set up, cross multiply
Distance formula
d = rt
Simple interest
I = Prt
Total cost
Units times price each
Unit conversion
Match units before solving

Substitution vs Elimination

Substitution

  • One equation solved
  • Plug into other

Elimination

  • Standard form equations
  • Add or subtract

Solved variable vs matching terms

Equation Method Picker

  1. One variable, linearIsolate the variable
  2. Fractions in equationMultiply by LCD
  3. Two equations, one solvedSubstitution method
  4. Two equations, standard formElimination method
  5. Equals zero, factors easilyFactor, zero product
  6. Quadratic won't factorQuadratic formula
  7. Dividing by a negativeFlip inequality sign

Expressions & Polynomials

Like terms
Same variable, same exponent
Distributive property
Multiply outside term, every term
Adding polynomials
Combine like terms only
Multiplying polynomials
Distribute every term (FOIL)
Translating phrases
Key words to operations
'Less than' phrase
Reverses subtraction orderCommon trap
Evaluating expressions
Substitute value, every instance

Linear Equations & Inequalities

Multi-step equation order
Distribute, combine, isolate variable
Equations with fractions
Multiply every term, LCD
Systems: substitution
Solve one, sub into other
Systems: elimination
Add or subtract, cancel variable
Inequality sign flip
Flip when × or ÷ negativeCommon trap
Open vs closed circle
Strict open, equal closed
Graphing inequality
Shade direction, mark boundary

Quadratics & Factoring

Factor x²+bx+c
Two numbers: multiply c, add b
Zero product property
One factor must be zero
Difference of squares
Factors into sum, difference
Quadratic graph shape
U-shaped parabola curve
Positive leading coefficient
Opens upward, has minimum
Negative leading coefficient
Opens downward, has maximum
Quadratic formula
Solves any quadratic equation

Slope-Intercept Memory

m is slope, b is start

m: rate of changeb: y-intercept valuex=0 finds b

Domain vs Range

Domain

  • Input values
  • x-axis values

Range

  • Output values
  • y-axis values

Input vs output

Graph Reading Picker

  1. Line crosses y-axisRead y-intercept(Set x=0)
  2. Line crosses x-axisRead x-intercept(Set y=0)
  3. Need rate of changeCalculate slope
  4. Graph curves, not straightNonlinear function
  5. Vertical line crosses twiceNot a function
  6. Comparing two linesCompare slope values

Slope & Linear Graphing

Slope formula
Change in y over x
Positive slope
Line rises left to right
Negative slope
Line falls left to right
Slope-intercept form
y = mx + b
y-intercept meaning
Starting value, where x is 0
x-intercept
Set y to 0, solve x
Parallel lines slope
Same slope value
Perpendicular lines slope
Negative reciprocal slope
Rate of change (table)
Change in y over x

Parallel vs Perpendicular Slope

Parallel

  • Same slope
  • Never intersect

Perpendicular

  • Negative reciprocal slope
  • Right angle meet

Same vs flipped-negative slope

Functions & Graph Features

Function notation f(x)
Output for input x
Evaluating f(3)
Substitute 3 for x
Vertical line test
One crossing per input
Domain
Set of input values
Range
Set of output values
Linear vs nonlinear
Constant vs varying rate
Function table check
Same input, one output
Reading graph context
Match features to meaning

Linear vs Nonlinear Function

Linear

  • Constant rate of change
  • Straight line graph

Nonlinear

  • Varying rate of change
  • Curved graph shape

Constant vs varying rate

Common Traps

Area vs volume units

Area = square units Volume = cubic units

Percent change base

Divide by original Not by new value

Negative divide flip

Flip inequality sign Only for negative ÷/×

Slope sign order

Same order both times Not mismatched x, y

Radius vs diameter

Use radius in formulas Diameter = 2× radius

Mean vs median pull

Mean shifts with outliers Median stays put

Function vs relation

One output per input Vertical line test

Last Minute

  1. 1.Test: about 46 questions, 115 min
  2. 2.Part 1: 5 questions, no calculator
  3. 3.Part 2: TI-30XS Multiview calculator allowed
  4. 4.Pass score: 145 out of 200
  5. 5.165+ = College Ready status
  6. 6.175+ = College Ready + Credit
  7. 7.Formula sheet given for whole test
  8. 8.Quantitative Problem Solving = 45% weight
  9. 9.Algebraic Problem Solving = 55% weight
  10. 10.Percent change: divide by original value
  11. 11.Flip inequality sign when dividing negative
  12. 12.Area: square units. Volume: cubic units
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