Logarithms

This is a little very usefull trick, which can make you stand from a crowd...
Works for base 10 log

1. Memorize this:

1 || 0
2 || .301
3 || .477
4 || .602
5 || .698
6 || .778
7 || .854
8 || .903
9 || .954
10 || 1
2. Let's try with 500
log 500 = log (5*100) = log 5 + log 100
log 100 = log 10^2 = 2
log 5 = .698
:. log 500 = 2.698

3. Now, let's a more complicated one
log 72 = log (7.2*10) = log 7.2 + log 1
log 7.2 = (we aproximate, remind that as it gets closer to 10 the increment is fewer) .86
log 1 = 1
:. log 72 = 1.86
real logarithm is 1.857

4. Still not convinced?, let'stry one more time
log 78543245 = log (7.8*10^7) = log 7.8 + 7
log 7.8 = .89
:.log 78543245 = 7.89
real logarithm is 7.895

try it yourself, it's fun and may get you some chicks... NOT