If you make 500 per week and claim 7 total dependents,how much state/federal tax will be taken from that check each week?

A salary of $500 per week is about $26,000 per year.

If you are married and have five kids, you should state on your W-4 that you are EXEMPT from tax withholding, because, with that many dependents and that low a salary, you will owe NOTHING come tax time.

Now, if you just want the amount withheld for "7" being claimed as # of exemptions, download Circular E from Internal Revenue Service and look it up!