model.rb

class CreditCard < ActiveRecord::Base
  attr_accessible :bank, :benefit_earn_rate, :benefit_type, :benefit_value, :interest, :name, :brand, 
                  :goal_name, :goal_cost, :goal_value

  @goal = @credit_cards.goal_cost.to_f / @credit_cards.goal_value.to_f
end

view.html.erb

<% @credit_cards.each do |credit_card| %>
  <tr>
    <td><%= credit_card.name %></td>
    <td><%= credit_card.bank %></td>
    <td><%= credit_card.brand %></td>
    <td><%= credit_card.interest %></td>
    <td><%= credit_card.benefit_type %></td>
    <td><%= credit_card.benefit_earn_rate %></td>
    <td><%= @goal %></td>
    <td><%= credit_card.goal_name %></td>
    <td><%= credit_card.goal_cost %></td>
    <td><%= credit_card.goal_value %></td>
    <td><%= link_to 'Show', credit_card %></td>
    <td><%= link_to 'Edit', edit_credit_card_path(credit_card) %></td>
    <td><%= link_to 'Destroy', credit_card, confirm: 'Are you sure?', method: :delete %></td>
  </tr>
<% end %>
</table>