How do you double numbers with exponents?

Double the coefficient. If the result is less than ten, leave the exponent as it is. If, as a result of doubling the coefficient becomes ten or more, then divide it by ten and increase the exponent by 1. Case I: 2.6*106 doubles to 5.2*106 Case 2: 5.2*106 doubles to 10.4*106 = 1.04*107