Rules for rounding off a measurement :
(i) If the digit to be dropped is less than 5, then the preceding digit is left unchanged.
(ii) If the digit to be dropped is greater than 5, then the preceding digit is increased by 1.
(iii) If the digit to be dropped is 5, then the preceding digit is increased by 1.
(iv) If the digit to be dropped is 5, then the preceding digit is left unchanged if it is even.
(v) If the digit to be dropped is 5, then the preceding digit is increased by 1 if it is odd.
