$10,000 invested at 10% simple interest over 10 years is 10000*0.1*10=$10000 interest, or PrT, where P is the principal amount ($10000), r is the rate as a fraction (10/100) and time T years.
Compound interest (compounded annually) generates (10000*1.1^10)-10000 interest, which is much higher at about $15937. This formula is A=P(1+r)^T, where A is the total amount (P+ interest). The fraction A/P is the growth. The interest is A-P.