Why doesn't this work?

I know I'm overlooking something obvious. I'm still experimenting trying to figure out how custom sheets work. I wish there was a more in depth tutorial somewhere. Does anyone know of one? Anyways. Why doesn't this work? <input type="number" name="Floop" style="height: 24px; width: 40px;"> <button type='roll' name='Test' value='Test: [[1d20+@{Floop}]]'/>

For Roll20, the name should start with attr_, so it should be something like: <input type="number" name="attr_Floop" style="height: 24px; width: 40px;"> <button type='roll' name='attr_Test' value='Test: [[1d20+@{Floop}]]'/>

HA! I'm a goof. That makes sense. It wouldn't work when I had both of them with attr_ on it so I removed attr_ from both and it still wouldn't work. Duh. Thanks!