Okay, here goes. You taking your 10 year old child, untrained, uncertified, for a dive at any depth, for any time, is just indicative of arrogance and ignorance. You are a relatively new diver. You are not a Rescue diver even, much less a DM or instructor. You are singularly unqualified to take your child on a dive. This is one of the people you value most in the world, yet you are sure that you can take care of her, when you are not experienced enough or properly trained. I am not attacking you, but simply amazed at the number of divers like you who think it's just fine. It's not. And taking your child down a line on your octo is just a picture that proves that you should not do this.
If she is in classes, you can certainly help her practice with her tables. Tables are not difficult or even 4th grade level. The instructor will teach her to use them and you can help her practice them.
I can say this to you from an instructor's viewpoint, and a parent of 2. My son was certified at 12, and my daughter at 10.
However, if your child cannot pass the course on her own, without your help, then she is not ready to be a diver, and you should be patient until she is ready.
Finally, please stop allowing your untrained children to dive. It is unsafe and you are modeling bad habits to the most important people in your life.