How do you determine the number of significant figures if a number does not have a decimal place?
It's normally determined by the first and last non-zero digit, but can be otherwise indicated...
By default, the number of significant figures is the number of digits in the run from the first non-zero digit to the last.
If you are given a number like
One convention that is sometimes used is to indicate the last significant digit with an overbar or underbar, e.g.
These examples have