3 ms·
You should factorize as n*10^m where m is even. Then the square root of the 10^m factor will be 10^(m/2), which then gives the order of the full square root.
by jonsen 12y ago
You should factorize as n*10^m where m is even. Then the square root of the 10^m factor will be 10^(m/2), which then gives the order of the full square root.
- mturmon 12y agoAnd one way to really internalize this is to start taking square roots (in your head, of course) of large numbers you see around you. Maybe license plate numbers if you're waiting in traffic. If you have extra time, you can do one step of refinement of your original guess, as done in the OP. ("Take the residual R, and the guessed-at factor p, and find the largest number N such that 2 * p * N <= R")