We need to use some helpers here to ensure that the amount is formatted correctly. Let's update this file:

```
<p><%= @payment.fullname %> has just become a backer of <%= @payment.campaign.name %>.</p>
<p>They contributed $<%= number_with_precision(@payment.amount.to_f/100.0 + @payment.user_fee_amount.to_f/100.0, precision: 2) %>!</p>
<p>Reach out and thank them by email: <%= @payment.email %>.</p>
```