the boundaries are 4 and 5 the smallest mixed number approaches 4 if we assume 4 then 4²=16 that is minimum, but it has to be slightly greater than 4 at least, so the product will be slightly greater than 16
the larges mixed number approaches 5 if we assume 4 then 5²=25 that is maximum, but it has to be slightly less than 5 at most, so the product will be slightly less than 25
