To count significant figures we have to remember the following rules:
• All non zero digits are always significant.
,• Interior zeros, that is, zeros between non zero numbers are significant.
,• Leading zeros, that is, zeros at the beggining of the number are not significant.
,• Trailing zeros, that is, zeros at the end of the number are significant if and only if there is a decimal point present in the number.
With this rules we have that:
a)
Since in the number 13001 we have interior zeros and these are significant we have 5 significant figures.
b)
Since this number have all non zero numbers it has 5 significant rules.
c)
Since we have a decimal point the trailing zero count, hence we have 3 significant figures.
d)
In this case we have leading zeros this are not significant, therefore we have 2 significant figures.
