1. MATHEMATICS Adding & Subtracting with Fractions

2. Lesson Objectives The aim of this powerpoint is to help you… to add fractions to subtract fractions

3. Adding & Subtracting Fractions You can ONLY add or subtract the same TYPE of fractions, so their bottom numbers MUST be the same. If the bottom numbers are different you will need to find equivalent fractions with the same bottom numbers. Once the bottom numbers are the same, you ONLY add or subtract the TOP numbers Remember to simplify your answer (if possible) at the end, IF the question asks you to.

4. Example 1 5 312 If you need to simplify your answer… 82 123 + = = ÷4  ÷4 5+3 8 1212

5. Example 2 3 5 412 9 512 If you need to simplify your answer… 41 123 – == ÷4  ÷4 – Different bottom numbers but 4 goes into 12, 3 times! x3 9 – 5 4 1212

6. Example 3 2121 7979 18 763 + == + Different bottom numbers! Cross-multiply (by bottom values)! x9x7 18 + 7 25 63 63

7. Quick Practice A 7 2D19 3 151520 20 B2 4E13 2 51520 5 C13F51C13F51 45924592 Work out your answers before clicking on to the next slide. + – + – – +

8. Answers

9. What next? Print out the notes called Frac4. Read them and make sure you answer any questions Work through all of the MyMaths lesson called Adding Subtracting Fractions found at: http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=fractions/addingFractions&taskID=1017 http://www.mymaths.co.uk/tasks/library/loadLesson.asp?title=fractions/addingFractions&taskID=1017 If you need more practice, try the worksheets called FracA-S0.xlsx and FracS-S0.xlsx. Now move on to the Frac-5 powerpoint