Common log and natural ln.
First do the logs (without calculator) of integer powers of 10.
Then the lns (without calculator) of integer powers of e. And ln ee
Then with calculator the logs of 1/2, 2, 20, 200, 2000. Notice the pattern!
Without calculator, what is log 20,000:_____
Then the logs of the "fives" : 1/5, 5, now continue without calculator: 50, 500, 5000.
Then the remainder with a calculator.