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# Adding, subtracting, multiplying, and dividing fractions

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### Adding, subtracting, multiplying, and dividing fractions

1. 2. Not the proper use of fractions:
2. 3. Adding Fractions <ul><li>When adding fractions the first step you need to know is the common denominator. </li></ul><ul><li>In the problem ½ + ¼ what is the common denominator? </li></ul><ul><li>The common denominator is 4 </li></ul><ul><li>After finding the common denominator whatever you multiply the bottom number by you need to multiply the top by. </li></ul>
3. 5. Adding Fractions <ul><li>Your problem should then change to: </li></ul><ul><li>2/4 + 1/4 </li></ul><ul><li>Now you add: </li></ul><ul><li>2/4 + 1/4 = 3/4 </li></ul><ul><li>Then check to see if you can reduce the fraction. To reduce ¾ you need to find one number that can evenly go in to ¾. </li></ul><ul><li>Can I reduce... NO! </li></ul>
4. 6. Subtracting Fractions <ul><li>Subtracting fractions are similar to adding fractions. Your first step is to find a common denominator. </li></ul><ul><li>In the problem ½ - ¼ what is the common denominator? </li></ul><ul><li>The common denominator is 4 </li></ul><ul><li>After finding the common denominator whatever you multiply the bottom number by you need to multiply the top by. </li></ul>
5. 8. Subtracting Fractions <ul><li>Your problem should then change to: </li></ul><ul><li>2/4 - 1/4 </li></ul><ul><li>Now you subtract: </li></ul><ul><li>2/4 - 1/4 = 1/4 Can I reduce... NO! </li></ul>
6. 9. Rule of Adding and Subtracting Fractions <ul><li>Remember one important rule of adding and subtracting fractions: </li></ul><ul><li>Whatever you do to the bottom of the fraction, you must do to the top of the fraction. </li></ul><ul><li>What this means is if you multiply the bottom number by 3 then you need to multiply the top number by 3. </li></ul>
7. 10. Multiplying Fractions <ul><li>Multiplying a fraction is the simplest of all fraction basics. </li></ul><ul><li>In the problem ¾ x ¼ all you need to do is multiply straight across and then see if you can simplify your answer. </li></ul><ul><li>¾ x ¼ = 3/16 </li></ul>
8. 11. <ul><li>Can I reduce... NO! </li></ul>Multiplying Fractions
9. 12. Dividing Fractions <ul><li>Dividing fractions is a lot like multiplying fractions, but there is one little trick. When you divide a fraction the rule is to flip the second fraction and multiply. </li></ul><ul><li>Example: ¾ / ¼, I am going to flip the ¼ and change it to 4/1 and then multiply it by ¾. </li></ul><ul><li>The problem should look like this 3/4 x 4/1. </li></ul>
10. 14. Dividing Fractions <ul><li>3/4 x 4/1 = 12/4 </li></ul><ul><li>We know have an improper fraction for our answer. An improper is when the top number is larger then the bottom number. </li></ul><ul><li>We need to change the improper fraction to a mixed number or a regular number. </li></ul><ul><li>We do this by dividing 12 by 4. </li></ul>
11. 16. Dividing Fractions <ul><li>12 divided by 4 = 3, 3 will be your final answer. </li></ul>
12. 17. Dividing Fractions <ul><li>Remember the most important rule of dividing fractions, is that you need to flip the second fraction and multiply. </li></ul><ul><li>FLIP AND MULTIPLY </li></ul>