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A counter that is capable of performing subtraction is called a reversible counter. It can be created using a combination of digital logic gates and flip-flops. The basic idea is to create a counter that can count both up and down by adding or subtracting a fixed amount at each cycle.

To create a reversible counter, we can use a combination of two counters: an up-counter and a down-counter. The up-counter counts up from 0 while the down-counter counts down from a maximum value. When we want to subtract a value from the counter, we add that value to the down-counter. If we want to add a value, we subtract it from the down-counter. When the down-counter reaches 0, we reset it to the maximum value and decrement the up-counter.

Through this method, we can create a counter that can perform both addition and subtraction operations.