[How to] Assign number row +/- keys?

[SpitFire-666]

Sorry if dumb question. I can't find a way to map the = and - number row keys for zooming (shown in pic).

I tried defining Plus, +, =, Equals etc in the keymap file but no dice

I'm on a laptop and the NumPad +/- keys work as designed (called Plus and Minus in the keymap), but since it's a laptop, you have to use the Fn key which takes 2 hands. Thoughts?