Important: coordination of pick-up/drop off, scheduling, school, health, etc. For these answer promptly or within a reasonable timeframe and answer honestly and as completely as you can.
Unimportant: general questions like "are they having fun today?", "how are they doing?", blah, blah, blah. This is her sticking her nose into your time with them. For these, if you respond at all keep it short. Promptness is not necessary. Answer at your convenience or not at all. You are not to be seen as hanging on her every text, waiting like a servant.
Me:49 W:45 M:19 T:22 EA confirmed and ended 8/2014 S:19,17 D:9,5