Remember how 増える is "to increase" (as in, something just increases, you aren't doing the increasing yourself). This one is that one, where you're doing the increasing. So, this word means to increase something. You know you're doing the increasing because you said "yes" (やす) to increasing something, and did it yourself.
The reading is the same like 増える. If you know that vocab word you probably can read this one as well.
I save all my homework for the weekend so I can spend more time with my family on weekdays.