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Comparing and Ordering Fractions. Lesson 3-7. Strategy. Make sure the denominators are the same. Compare the numerators. If the denominators are not the same, then rewrite the fractions using a common denominator. The new fractions should be equivalent to the original fractions.
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Comparing and Ordering Fractions Lesson 3-7
Strategy • Make sure the denominators are the same. • Compare the numerators. • If the denominators are not the same, then rewrite the fractions using a common denominator. • The new fractions should be equivalent to the original fractions.
Writing Equivalent Fractions • One way to find a common denominator is to multiply the two original denominators. 5 3 > 4 6 6 x 4 = 24 20 > 18 x 4 x 6 18 20 24 24
Another way to compare fractions is to find the LCM of both denominators. • Use the LCM as the new denominator in the equivalent fractions. 7 5 < 9, 18, 27, 36, 45 9 12 12, 24, 36, 48, 60 20 < 21 x 3 x 4 20 21 36 36
Ordering Fractions • Find the LCM of the denominators. • Use the LCM to write equivalent fractions. • Put the fractions in order using the numerators.
Example - Order from Least to Greatest: 3 2 1 5 8 4 x 8 x 5 x 10 15 16 10 40 40 40 8, 16, 24, 32, 40, 48 1/4 < 3/8 < 2/5 5, 10, 15, 20, 25, 30, 35, 40 4, 8, 12, 16, 20, 24, 28, 32, 36, 40