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GRE Math

  1. Percent Change
    (Amt change/ original amt) x 100
  2. Exponent opperations
    • **Need the same base**
    • Multiplying exponents: add the exponents and keep the same base
    • Dividing exponents: subtract the exponents and keep the same base
    • Raise a power to a power: multiply the exponents
    • Negative exponents: 1/exponent expression
    • Fraction exponents: root of the expression

    **Do NOT add or subtract exponents or roots**
  3. Absolute Value
    Never negative
  4. Multiplying Binomials
    FOIL
  5. Factoring Squares
    Factoring Binomials
    a2 - b2 = (a-b)(a+b)

    a2 +2ab + b2 = (a+b)2 a2 -2ab + b2 = (a-b)2
  6. Quadratic Equation
    ax2 + bx + c = 0
  7. Finding the distance between two points

    Midpoint
    d= sqrt (x1-x2)2 + (y1- y2)2

    M= (x1+x2)/2 , (y1+y2)/2
  8. Slope

    Midpoint
    • m=slope= rise/run
    • (y1-y2) = m(x1-x2)
  9. Circles and Angles (central and inscribed)
    central: angle = arc

    inscribed: angle = arc x2
  10. Area of a triangle
    (1/2)base x height
  11. Adding fractions
    "magic x"

    (3/7) + (2/9) = 7

    • 3x9 = 27
    • 7x2 = 14
    • 41

    9x7 = 63 (41/63) = 7
  12. Polygons
    • (3+ sides)
    • sum of interior angles: (n-2)180

    sum of exterior angles: 360
  13. Types of triangles
    • Isosceles: 2 equal sides and angles
    • Equilateral: 3 equal side and angles
    • Right: 90 degree angle: a2 + b2 = c2

    3-4-6: 6-8-10

    30-60-90: x - sqrt3 - 2x

    5-12-13

    45-45-90: 1 - 1 - sqrt 2
  14. Parallelograms
    A = base x height

    supplemental angels = 180
  15. Circles
    Circumference: 2(pi)r

    Area: (pi)r2
  16. Surface area
    -rectangular solid
    -cube
    rectangel: 2lw + 2wh + 2lh

    cube: 6s2
  17. Volume
    -Rectangle
    -Cube
    -Cylinder
    • Rectangle: lwh
    • Cube: l3
    • Cylinder: (pi)r2h
  18. Trapezoid
    (one pair parallel sides, one pair non-parallel)

    a=(( s1 + s2)/2) xh
  19. Fractions: Decimals: Percentages to Know
    • (1/2) : 0.5 : 50%
    • (1/3) : 0.33 : 33.3%
    • (1/4) : 0.25 : 25%
    • (1/5) : 0.2 : 20%
    • (2/3) : 0.66 : 66%
    • (3/4): 0.75 : 75%
  20. Percent increase/decrease
    • Percent increase: (amt of increase/original whole) x100
    • Percent decrease: (amt of decrease/original whole) x100
  21. How to recognize multiples
    • 2: Last digit is even
    • 3: Sum of digits is a multiple of 3
    • 4: Last two digits are a multiple of 4
    • 5: Last digit is 5 or 0
    • 6: Sum of digits is a multiple of 3 and last digit is even
    • 9: Sum of digits is multiple of 9
    • 10: Last digit is 0
    • 12: Sum of digits is a multiple of 3, and last two digits are a multiple of 4
  22. Common Squared Numbers
    • 1: 1
    • 2: 4
    • 3: 9
    • 4: 16
    • 5: 25
    • 6: 36
    • 7: 49
    • 8: 64
    • 9: 81
    • 10: 100
    • 11: 121
    • 12: 144
    • 13: 169
    • 14: 196
    • 15: 225
  23. Common Square roots
    • 225: 15
    • 196: 14
    • 169: 13
    • 144: 12
    • 121: 11
Author
lsleiter
ID
40214
Card Set
GRE Math
Description
Formulas
Updated

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