The number of digits in N (positive integer) = floor(log_10(N)) + 1. The integer part of log_10(N) is the characteristic. For N = 5^30: log_10(5^30) = 30log_10(5) = 300.6990 = 20.97, so digits = 20 + 1 = 21. For finding leading zeros after decimal: if 0 < N < 1, the number of zeros immediately after the decimal point = |floor(log_10(N))| - 1. Example: (1/2)^10 = 1/1024, log_10(1/1024) = -log_10(1024) = -3.010, floor = -4, zeros = 4 - 1 = 3 (i.e., 0.000976...). JEE gives log_10(2) and log_10(3) as data.