First change the mixed fraction to improper fraction, and then find common denominators.
5 1/2 = 11/2
4/9(2/2) = 8/18
11/2(9/9) = 99/18
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Next, subtract
99/18 - 8/18 = 91/18
91/18 = 5.05
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As you are finding the best estimate, 5.05 is closest to 5, which makes your answer D)
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hope this helps
