To fill in the blank and make two fractions equivalent, you need to understand the concept of equivalent fractions. Equivalent fractions are different fractions that represent the same value. For example, 1/2 is equivalent to 2/4. To find an equivalent fraction, you can multiply or divide the numerator and denominator of a fraction by the same non-zero number. Without the specific fractions provided, it's impossible to determine the exact value needed to fill in the blank.