Fractions :

 

 

Reciprocals:

Reciprocals are two numbers whole product is 1. Every number except 0 has exactly one reciprocal. Zero has no reciprocal.

Ex:
2 and 1/2 are reciprocals: 2 x 1/2 = 1

3/4 and 4/3 are reciprocals: 3/4 x 4/3 = 1

-3/4 and -4/3 are reciprocals: (-3/4) x (-4/3) = 1

Notice that a positive number has a positive reciprocal, and a negative number has a negative reciprocal, and a negative number has a negative reciprocal. Also a whole number like 5 can be written 5/1.



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Combining Fractions

When adding/subtracting fractions with the same denominator you combine the numerators. But, when combining fractions with different denominators, just rewrite them as equivalent fractions with the same denominator.

 

Same Denominator

Addition


Subtraction


Different Denominator

Multiplying and Dividing Fractions

When multiplying fractions, you simply multiply the numerators and the denominators. But, when dividing fractions, multiply by its reciprocal.
 

Multiplying


Dividing

 

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