Sunday, March 27, 2011

Dividing Fractions; "Reciprocal"

This first video is not very loud, and parents of younger children may want to simply use it as an example of how to teach the concept.

I show first (by drawing it out) that 6/2 = 3, then show how 6 divided by ½ cannot equal 3, but instead equals 12.  Use several examples of this.  12/4 = 3, but 12 divided by ¼ = 48.

(1) Visual aid of how inverting (flipping upside down) the second term, then multiplying the fractions will actually give the correct result.  =)

(2) A reciprocal is an inverted fraction, that when multiplied by the original fraction, gives an answer of 1.
When dividing fractions, you invert (flip upside down) the second term.  This inverted fraction is the reciprocal of the original fraction, and vice versa.
You cannot invert mixed fractions.  You would need to change a mixed fraction into an improper fraction first.

(3) Dividing fractions, part 1

(4) Dividing mixed numbers

(5) Dividing fractions, part 2

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