# MATHEMATICS Equivalent Fractions. Lesson Objectives The aim of this powerpoint is to help you… to find equivalent fractions to simplify or cancel fractions.

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MATHEMATICS Equivalent Fractions

Lesson Objectives The aim of this powerpoint is to help you… to find equivalent fractions to simplify or cancel fractions down to compare and order fractions

Equivalence 2 out of 4 parts shaded 3 out of 6 parts shaded6 out of 12 parts shaded

Finding Equivalent Fractions 2323 2323 ×5 10 ×5 15 ≡ 2323 ×100 200 ×100 300 ≡ ×2 4 ×2 6 ≡

Cancelling Fractions Down 24 36 ÷2 6 ÷2 9  ÷3 2 ÷3 3  ÷2 12 ÷2 18  HINT: Sometimes the biggest number you can divide by is the difference between the two numbers in the fraction! You may have spotted that 24 and 36 are both in the 12 times table so you could have simply divided BOTH numbers by 12! 24 36 ÷12 2 ÷12 3 

Quick Practice Q1 = = = =

Answer to Q1 2 10 16 510 55 Compare known numbers in both fractions… = = = = 4 The bottom 5 x 2 gives the bottom 10 so multiply the top 2 by 2 to get… The top 2 x 5 gives the top 10 so multiply the bottom 5 by 5 as well to get… The top 2 x 8 gives the top 16 so multiply the bottom 5 by 8 as well to get… The bottom 5 x 11 gives the bottom 55 so multiply the top 2 by 11 to get… 2540 22

Quick Practice Q2 Cancel each of the following fractions down to their simplest form. A25C 70 40100 B14D28 1842 Work out your answers before clicking on to the next slide. = = = =

Answer to Q2 A25 40 B14 18 C 70 100 D28 42 = = = = Both numbers end in 5 or 0 so divide them BOTH by 5 The difference between the two values is 14 and BOTH numbers can be divided by 14! Both numbers end in 0 so divide them BOTH by 10 Both numbers are even so divide them BOTH by 2 5 8 7 9 7 10 2 3

Comparing Fractions To compare fractions you may need to find equivalent fractions with the same bottom number. The easiest way is to multiply the top and bottom of each fraction by the bottom of the other fraction(s) Remember to quote the ORIGINAL fractions (not their equivalents) in your answer.

Example 75 > 72 so 5 / 8 > 9 / 15

Quick Practice

Answers 1 / 3  (x8)  8 / 24 3 / 8  (x3)  9 / 24 8 is smaller than 9, i.e. 8 < 9 < < > = 7 / 10  (x3)  21 / 30 2 / 3  (x10)  20 / 30 21 is bigger than 20, i.e. 21 > 20 5 / 6  (x15)  75 / 90 13 / 15  (x6)  78 / 90 75 is smaller than 78, i.e. 75 < 78 28 / 35  (x5)  140 / 175 4 / 5  (x35)  140 / 175 These are EQUAL!