Manual entity with + and -

Hi there.
Is there a way to add a manual entity with a value of my choice? And also with button + and - so I can add or remove from state value given before.

The reason for this is:

I have a pellets heater in my house and I want to track how many pellets bags I have left in storage.

For example
Yesterday I had 100 bags in storage.
Today i fill up my heater with 10bags.

After I fill up my heater with 10bags I want to press “-” button 10 times or input 10 in a field and press “-”
And taaadaaa now my entity / state will be “Pellets left / 90 bags”

I don’t have a clue how to perform this so it will be visually in my fui of HA.
Can someone please point me in the right direction or tell me it’s not possible at this time.

Use a counter and the increment / decrement service: