Final answer:
The only proper fraction provided in the question is 4/9. A proper fraction is defined as a fraction where the numerator is less than the denominator. All the other fractions mentioned in the question don't meet this criterion.
Step-by-step explanation:
In mathematics, a proper fraction is defined as a fraction where the numerator (the number on the top) is less than the denominator (the number on the bottom).
From this, we can conclude that out of the fractions provided (4/9, 5/4, 6/2, 9/7, 8/8), the only proper fraction is 4/9. In 4/9, the numerator 4 is less than the denominator 9.
Other fractions like 5/4, 9/7, and 6/2 are improper fractions because their numerators are greater than their denominators and 8/8 is not a proper fraction because it equals to 1.
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