Why can I call this <td><%= team.players.sum(:misses) %></td> and this <td><%= team.players.sum(:misses) %></td>
but this gives me 0 (some do not have 0 for misses) <td><%= team.players.sum(:hit) / team.players.sum(:misses) unless team.players.sum(:misses) == 0 %></
Say hits = 2 and misses = 4. In Ruby, 2/4 = 0. However, 2.0/4.0 = 0.5. Try those expressions in irb.
To solve your problem, you could convert the numbers to floats: hits.to_f / misses.to_f = 2.0 / 4.0 = 0.5.
The docs for Number#divmod might be helpful. http://www.noobkit.com/show/ruby/ruby/ruby-core/numeric/divmod.html
Craig