Rails Gets Errors in Saving to Intermediate Tables and Retrieving Data from Other Tables

NoMethodError in Purchases#index
Showing/home/ec2-user/environment/RepeatAlart_app/app/views/purchases/index.html.erb where line #18 raised:

undefined method `name' for 1: Integer
Extracted source (around line #18):

16<tr>
17<td><%=purchase.user_number%></td>
18<td><%=purchase.user_number.name%></td>
19<td><%=purchase.product_number.brand%>/td>
20<td><%=purchase.product_number.name%>/td>
21<td><%=purchase.created_at%>/td> 

class User<ApplicationRecord    
values:name,presence:true,length:{maximum:50}
values:number, presence:true
has_many —Purchases
has_many:products, through::purchases
belongs_to —salon
end

class Product <ApplicationRecord
values:brand,presence:true
values:number, presence:true
values:name, presence:true
values:term, presence:true
values:name, unique:true
has_many —Purchases
has_many:users,through::purchases
belongs_to —salon
end

class Purchase <ApplicationRecord
    belongs_to:user, optional:true
    belongs_to:product, optional:true
    belongs_to —salon
end

class PurchasesController <ApplicationController
  def index
    @purchases=Purchase.where(salon_id:current_salon.id)
    @purchase=Purchase.new
  end

  def create
    @purchase=Purchase.new(purchase_params.merge(salon_id:current_salon.id))
    [email protected]
      flash[:success] = "Success!"
      redirect_to "/purchases"
    else
      redirect_to "/purchases"
    end
  end

  default
      @purchase=Purchase.find (params[:id])
  end

  default update
      purchase=Purchase.find (params[:id])
      purchase.update(purchase_params)
      redirect_to "/purchases"
  end 

  def destroy
     Purchase.find(params[:id]).destroy
    flash[:success] = "deleted"
    redirect_to "/purchases"
  end

   private

     def purchase_params
      param.require(:purchase).permit(:user_number,:product_number)
     end  
end

<h1>List of purchased items</h1>
        <table class="table">
            <thead>
                <tr>
                 　 <th>Customer No.</th>
                　  <th>Customer Name</th>
                　  <th>Brand </th>
                 　 <th>Product Name</th>
                　  <th>Date of purchase</th>
                　  <th>Next Purchase Recommendation Date</th>
                    <th colspan="2"></th>
                </tr>
            </thead>
            <tbody>
                    <%@purchases.each do | purchase | %>
                <tr>
                    <td><%=purchase.user_number%>/td>
                    <td><%=purchase.user_number.name%>/td>
                    <td><%=purchase.product_number.brand%>/td>
                    <td><%=purchase.product_number.name%>/td>
                    <td><%=purchase.created_at%>/td>
                    <td><%=purchase.limit_date%>/td>
                    <td><%=link_to "Edit", "#", class: "btn btn-primary mr-3" %>/td>
                    <td><%=link_to "delete", purchase, method::delete, class:"btn btn-primary mr-3"%>/td>
                    <%end%>
                <tr>
             </tbody>
        </table>      

<h1>Register Purchase Information</h1>

<div class="row">
  <div class="col-md-6col-md-offset-3">
    <%=form_for(@purchase)do|f|%>
      <%=f.label: user_number%>
      <%=f.number_field:user_number,class:'form-control'%>
      <%=f.label:product_number%>
      <%=f.number_field:product_number, class: 'form-control'%>

      <%=f.submit "Register Purchase Information", class: "btn btn-primary" %>
    <%end%>
  </div>
</div>