"Seventeen rabbits are more than ten rabbits."
Translation:שבעה עשר ארנבים הם יותר מעשרה ארנבים.
It makes the sentence structure clearer. If you just said " שבעה עשר ארנבים יותר מ-10 ארנבים" it might be confusing, are you saying 17 more than 10, so a total of 27 rabbits? And if so, what about them? Using הם just signposts the fact that you are identifying 17 rabbits as being more than ten rabbits and that the sentence doesn't have a further predicate about all those rabbits together. I think.... Any native Hebrew speaker please correct if this is inaccurate
They're both masculine. In the numbers from one to ten, most of the masculine numbers end with a "hay" and an ah sound. Then in the teens, the masculine ones have that ah sound on the number part, and are followed by asar (no ah sound). The feminine teens have their normal sound for the first half, followed by esre (which does end in "hay"). If you go to Wikipedia "Hebrew Numbers" you can see a chart which shows this.
The numbers in Hebrew are strange and a bit complicated. With masculine nouns they take what SOUND like the "feminine" forms of regular adjectives, and vice versa, and then for numbers above ten it's -asar (m) and -esreh (f). Please don't look for logic, it's just something we have to learn. Ringcyle explained this a year ago in this very discussion page.