My ex keeps texting me parenting questions on MY days with the kids

Like, "does she have a spelling test" or "what time is soccer" - things that I would know because SHE'S WITH ME. It's constant. And when I don't answer right away, she calls and leaves voicemails. I get that she cares but I'm trying to be present with my kids and I'm not her personal assistant. How do I set this boundary without being a jerk about it?