I kinda know how a redstone comparator works.

*mumbo jumbo intensifies*

Today is your lucky day, you will learn how a comparator works, the mode where the torch is on, it adds all the inputs (it can come from left, right, or/and the back [the back end of the comparator MUST have an input]) an input is how powerful the redstone input is. For example, main input (6) + any other input (left) 4 and (right) 5, the total is 15. When the torch is on, it subtracts the main input (back of the comparator) to any other inputs (left and/or right) for example main input (15 or puting a lever behind the comparator) and left and right (3 and 4), you get 8.

Essentially, when the torch is off, it adds, when the torch is on, the comparator subtracts, it also can detect how many items are in a storage container (chest, hopper, or shulker boxes.)