No easy answers here. I agree that making your grocery day a lighter school day would help. For us that would mean dropping the basics (writing, spelling, math & such) and only reading books (Bible, poetry, history & such) – in other words, only the fun stuff.
I often go to the grocery store in the evening while one child is in a scouting activity with Dad, so that leaves me with “only” 3 kids at the store with me. Not necessarily easier but we get it done. My husband is amazingly helpful and drops by the store on his way home from work sometimes or goes with us on the weekend.
The most helpful for me was training the kids to help, not only at the store but also at home unloading and putting away. The young ones don’t do much that is “helpful” but at least they know it’s not a good time to make demands of Mommy to make them a snack or something – that always drove me crazy. My husband did most of that training – bless him! – and it runs smoother now. Smoother does not mean perfect, of course.
In all honesty, when I had a toddler (my kids are 10, 8, 6, & 4 now), the best for me was hiring a babysitter to come for an hour or two once a week, while I ran errands. Not helpful on the budget, I know, but it was helpful for me. It was also helpful for my husband, since I wasn’t running out the door as soon as he arrived home.
Joy