I took an average menu and figured out the cost per day per child and write that off - I keep ALL my receipts to be able to back up my math ... so last year I had receipts for groceries totalling just on $20,000 and I wrote off just on $8000.00 for daycare which left $12,000 for my family of 2.5 which IMO is a reasonable split considering sometimes the 5 kids eat more at a meal than my spouse and I do