16/5'9/161 lbs.

https://imgur.com/a/UnkyL

Lift 5x a week, and I've been doing cardio for 10 mins 3x a week. I'd like to get lean enough so that I can start bulking and actually add muscle.

I'm surprised by how light I'm having to get in order to start seeing abs.

Should I start throwing in ab work, and if so how frequently?

Any help and insight would be appreciated.