Monday, December 13, 2010

Fractions

Fraction- a quantity that is less than a whole unit, an ordered pair of integers a&b, with b not equaling 0, written as a/b, the integer a is the numerator and b is the denominator.

Models-
  • Part to Whole-
    • you must agree on a unit (cups, inches, centimeters, ect.)
    • you must understand that the unit is subdivided into b parts of a equal sizes
    • and that you are only considering a certain number of parts
  • Color Region (Area Model)-
    • a shape chosen to represent unit which is visualized by coloring some of the regions.
  • The Set Model-
    • A finite set of objects(u) is chosen to represent the unit which is divided into n(u)= equal parts A fracction is visualized by circling the number of objects that represent numerator of fraction
  • Number Line-
    • portions of the number line is subdivided into equal size parts

Simplifying Fractions-
  • when the numerator and the denominator of a fraction have a common factor that is greater than one they can both be divided by that common factor inorder to reduce the fraction into smallest terms.
Common Denominator-
Fraction Bars-
 This shows that 1/2 and 3/6 is equal and also that 1/3 and 2/6 are equal.

Rules of Signs for Fractions-
-7/9= -7/-9 FALSE
-5/-12= 5/-12 TRUE
3/-5=-3/5 TRUE

Mental Calculation and Estimation-
which is smaller? 1/7 or 1/10    1/10 is smaller
which is larger? 2/3 or 1/3     2/3 is larger
are they equal? 1/3 and 2/6   yes

Rounding-
9//12 almost 1
7 1/5 almost 7




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