Hello, arjh, and welcome!
Your question is actually quite a bit more complicated than you probably realized.
In general, if you are just buying your lunch at work, those costs cannot be claimed on your tax return. However, there are some times that you can claim meal costs associated with work.
For example - imagine your company has offices in Chicago and Madison. You work in Chicago, and a package that was supposed to be delivered to Madison shows up in your office. Your boss sends you to the Madison office to get the package there ASAP. Since you will be on the road during your normal lunch time, you stop to eat while en route. If your company does not reimburse for the cost of your meal, you could claim it on your taxes. However, the cost of just one meal
wouldn't be enough to make a difference, since you would need to be using itemized deductions (schedule A) - and even then, the total claims in this particular part of your itemized deductions have to be greater than 2% of your adjusted gross income.
Child care costs are treated in a completely different fashion. There is a separate form (2441) for claiming expenses associated with child care. Those expenses must be paid to a child care provider (either an individual or a day care). Based on your income, there is a percentage of those expenses that will be calculated as a credit against your taxes.
Costs related to your child's schooling are not deductible on the federal return. Depending on your state, it might be possible to claim those costs. (I know Minnesota has this credit, but am not aware of any others.)