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Adding Fractions

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Adding Fractions

  1. 1. How do I add fractions to fractions? Fractions lesson 6 Integrated 1A
  2. 2. What is ? <ul><li>One way to do this is to draw pictures and cut them up and combine them. </li></ul>
  3. 3. There is a better way <ul><li>This is the part that confuses students most often. </li></ul><ul><li>You must sometimes change fractions to show the same type of parts. </li></ul><ul><li>Using equal fractions makes this easier. </li></ul>
  4. 4. Let’s begin with equal fractions. <ul><li>Let’s start with one half and make a list of equal fractions. </li></ul>Make a new fraction that is equal to one half. Multiply the top number (1) by 2. Multiply the bottom number by the same 2.
  5. 5. Let’s multiply one half by <ul><li>Now our list should look like this. </li></ul>
  6. 6. Add Another Fraction <ul><li>Let’s add another fraction to our list in our notebook. </li></ul><ul><li>Start with the first number – one half. Multiply top and bottom by 4 this time. </li></ul><ul><li>Write the new fraction. </li></ul>
  7. 7. Add Another Fraction <ul><li>What comes next? Write the new fraction. </li></ul>
  8. 8. Add More <ul><li>Continue this list in your notebook. </li></ul><ul><li>What comes next? Write the new fractions. </li></ul>
  9. 9. Let’s multiply one third by <ul><li>Now our list should look like this. </li></ul>
  10. 10. A new list <ul><li>Start with one-third </li></ul><ul><li>Multiply the top and bottom by three. Do the same for the next one by multiplying one-third by four. </li></ul>
  11. 11. Going from the known to the unknown <ul><li>In a previous lesson last week, you divided top and bottom by the same number. </li></ul><ul><li>You didn’t change the value of the fraction, just the appearance. </li></ul>
  12. 12. Is one-fourth equal to two-eighths?
  13. 13. Add these two fractions making them both a certain number of eighths We can’t easily add fourths to eighths so we find a number to multiply times four to get eight on the bottom. x2 x2
  14. 14. We are making a addition problem that becomes easier to work with. One eighth doesn’t need to be changed, So just rewrite it. x2 x2
  15. 15. Now add down the right side. Six-eighths plus one-eighth is how many eighths? 7
  16. 16. Get a worksheet (F6) <ul><li>What is the least common multiple of four and 8? </li></ul><ul><li>(What is the smallest number in both lists?) </li></ul><ul><li>Use eight as your common denominator. </li></ul>Multiples of 4: 4, 8, 12, 16, 20, 24… Multiples of 8: 8, 16, 24, 32… Terms :
  17. 17. Make your denominators the same. <ul><li>What can you multiply by four to get eight? </li></ul><ul><li>The bottom number is already in eighths, don’t change it </li></ul>x2 x2
  18. 18. Add. <ul><li>Now add the column with the common denominators </li></ul><ul><li>Is five-eighths in simplest form? </li></ul>x2 x2
  19. 19. Worksheet #5 <ul><li>What is the least common multiple of 2 and 6? </li></ul><ul><li>(What is the smallest number in both lists?) </li></ul><ul><li>Use SIX as your common denominator. </li></ul>Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16… Multiples of 6: 6, 12, 18, 24, 30…
  20. 20. Make your denominators the same. <ul><li>What can you multiply by two to get six? </li></ul><ul><li>The bottom number is already in sixths, don’t change it </li></ul>x? x?
  21. 21. Add down the right column. <ul><li>Put your answer into simplest form, if necessary. </li></ul>x3 x3
  22. 22. Worksheet #9 <ul><li>What is the least common multiple of 5 and 10? </li></ul><ul><li>Use FIVE as your common denominator. </li></ul>Multiples of 5: 5, 10, 15, 20, 25, 30,… Multiples of 10: 10, 20, 30, 40, 50…
  23. 23. Make your denominators the same. <ul><li>What can you multiply by five to get ten? </li></ul><ul><li>The bottom number is already in tenths, don’t change it </li></ul>x? x?
  24. 24. Is your answer in simplest form? <ul><li>Add the numbers down the right column. </li></ul>

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