If you are in a 28% tax bracket, and you want a check to equal (net) $10,000, what formula do you use?
Assuming the only difference between your gross and net amounts is the tax, then in general:
Net is what you have after you subtract tax, or net = gross - tax. The tax amount = gross * tax rate, or (gross*0.28)
Net = Gross - (Gross * tax rate). For your example, express the 28% as 0.28
10000 = Gross - (0.28)(Gross); 1000 = 0.72 Gross
Divide both sides by 0.72: Gross = $13,888.89