Recording of Figures : Accuracy can also be affected by the way you record figures. This should be done as precisely as possible. Figures recorded should show all the certain digits, and add also the final estimated or uncertain digit. For example, suppose a voltmeter has a guaranteed specification of 1%. A measurement is taken and the voltmeter reading is 125.1 1 V. From the known accuracy (+ I %) it is therefore obvious that the actual voltage lies between 125.1 1 + 1% = 126.361 1 and 125.1 1 - 1% = 123.87128 volts. It can be seen that the only certain digits are the 100 and the 20. We know it is one hundred and twenty something! The 5 is the final estimated or uncertain digit, and all the others are meaningless, given the accuracy of the instrumentation.

As a rule of thumb guide the following might be useful:

If your estimated error is between 50% and 5%, record 2 significant digits.

If your estimated error is between 4.09% and 0.5%, record 3 significant digits.

If your estimated error is between 0.49% and 0.05%, record 4 significant digits.

Another point that you should keep in mind is, for scientific reporting large numbers should be shown by index notation.

e.g., 4,230,000 as 4.23 x 10⁶.