Fill in the blank to rewrite $9$9 as a fraction:
$9=\frac{9}{\editable{}}$9=9
Fill in the blank to rewrite $15$15 as a fraction:
Fill in the blank to rewrite $1$1 as a fraction:
Which of the following models the fraction $\frac{3}{1}$31?
Explain equivalence of fractions in special cases, and compare fractions by reasoning about their size.