Derek buys the school supplies including tax for boxes of pencils that cost 1.57 for each box one notebook that cost 3.28 one binder that costs 4.36 how much money does Derek spend on school supplies?
The total cost for the boxes of pencils is 1.57 * 4 = $<<1.57*4=6.28>>6.28.
The total cost of the pencils, the notebook, and the binder is 6.28 + 3.28 + 4.36 = $<<6.28+3.28+4.36=13.92>>13.92 Derek spends on school supplies. Answer: \boxed{13.92}.