NOTES: Rounding Whole numbers to N significant figures: We round numbers if we only need a reasonable approximation rather than the exact value. Whole number i.e.: numbers without any decimal point (the decimal point is implied).eg:120980 The first significant figure in a number is the first non-zero digit (reading from left to right). All digits from 1-9 are significant. Zeros in between non-zero digits are also significant.eg: 2302006.all zeros in this number are significant because they occur between two non-zero digits. How to round a WHOLE number to certain number of significant figures: Steps: 1. Decide where you want to cut off the number, and mark a "cutoff point". 2. If the digit after the cut-off point is 5 or more, then increase the digit(s) before the cut-off point by one. 3. Remove all the digits after the cut-off 4. Fill any gaps left, after removing the cut-off digits, with zeroes. 64,492 might have been the exact number. When we round off 64,492 to two significant figures, it is 64,000. The first non-zero digit, reading from left to right in a number, is the first significant figure. e.g. In 64,492 , 6 is the first significant figure.(sig.fig.) When we round off 64,492 to two sig. figs, that means in the answer we should have two non zero figures.The third figure(which is 4) is less than 5, so we drop them to zeros. round off 64,492 to: (a) 1 significant figure (b) 2 significant figures (c) 3 significant figures (d) 4 significant figures (e) 5 significant figures which is 60,000 which is 64,000 which is 64,500 which is 64,490 which is 64,492 The accuracy of the answer will depend on the number of significant figures. The answer will be more accurate, if it is given to a higher number of significant figures. 64,492 is the most accurate answer and it is given to 5 sig. figs. *** The trailing zeros in a whole number are not significant.There are used to keep the other figures in there correct places. eg. 64000 6 and 4 are significant not the zeros.