Creating Common Denominators

Remember that if you multiply the top and bottom of a fraction by the same number it does not effect the value of the fraction.

Example 1: If we have the fraction 2/3, we can multiply the top and bottom by 2, and not change its value:

(2/2) X (2/3) = (4/6)

2		2		4
---	x	---	=	---
3		2		6

If we reduce the equivalent fraction of 4/6, we get the original number, 2/3.

Example 2: If we have the fraction 2/3, we cn multiply the top and bottom by 5, and not change its value:

(5/5) X (2/3) = (10/15)

2		5		10
---	x	---	=	---
3		2		15

If we reduce the equivalent fraction of 10/15, we get the original number, 2/3.

Why does this method work? Any number divided by itself equals one. 2/2 =1 and 5/5=1, etc Any number multiplied by 1 equals itself! The point is you do not change the value of a fraction if you multiply its top and bottom numbers by the same number.

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