Logarithms shrink lengthy numbers
You will see later that:
log (10) = 1 log (0.1) = –1
log (100) = 2 log (0.01) = –2
log (1000) = 3 log (0.001) = –3
log (10000) = 4 log (0.0001) = –4
log (100000) = 5 log (0.00001) = –5
log (1000000) = 6 log (0.000001) = –6
You can see that the logarithm of a seven digit number (1000000) is just 6 and that of 0.000001 is -6 only, which are easy to remember and deal with.