subtractively

At the far end, he emerges in a public space modeled on a Menger sponge -- a cube diced subtractively with ever-smaller cubic volumes until its surface area tends toward infinity.

Asimov's Science Fiction 2004

If, now, a current flow in the ringer winding from plus to minus, obviously the right-hand pole will be additively magnetized, the current tending to produce north magnetism there; also the left-hand pole will be subtractively magnetized, the current tending to produce south magnetism there.

Cyclopedia of Telephony & Telegraphy Vol. 1 A General Reference Work on Telephony, etc. etc. George Patterson 1910

Taking any quantity a negative number of times, means that the sum of the units in the quantity taken the given number of times is to be found subtractively, and suggests the processes of both addition and subtraction,

Considerations on the measures carrying on with respect to the British colonies in North America 1774