First find the characteristic by observation.

1.If no>1, characteristic = (no of digits before deimal-1)

eg for 1352, characteristic is 3 (ie 4-1)

If no is <1, take mantissa as bar(no of zeros before 1st digit.)

eg for 0.02 charact = bar 2. (written as 2 with a dash above it)

2.Find Mantissa from log table. Choose the first 2 nos from the leftmost column. there will be nos like 10, 11, 12, ...

3.then take the 3rd digit of the original no from the columns that are just to the right of the first coulmn (0 to 9)

For 4th take the no from the table "mean difference" and add it to the no u get from step 2 & 3.

eg. log 1352= 3.1303+0.0006= 3.1309