Final answer:
To count significant figures in a number without a decimal, start from the first nonzero digit on the right and include all digits until the last nonzero digit, unless there's a trailing zero, which may not always be significant. Option 2 is the correct answer.
Step-by-step explanation:
When determining the number of significant figures in a number without a decimal point, it is crucial to understand how to treat zeros, as they can affect the accuracy and precision of a measurement. To find the significant figures, you start with the first nonzero digit on the left and count this digit and all remaining digits to the right as significant, unless the last digit is a trailing zero. Thus, zeros in front of all nonzero digits, known as left-end zeros, are never significant and only serve to place the significant digits in their proper positional values. Consequently, zeros that come after all nonzero digits without a decimal point, or right-end zeros, are not always significant; their significance can often be determined by the context or additional formatting, such as a bar over the last significant figure or an indication of the level of precision.
For example, in the number 0.005290, the 5, the 2, and the 9 are significant based on rule 1 (all nonzero digits are significant), and the trailing zero is also significant due to rule 5. However, the leading zeros are not significant as per rule 3. If we consider a whole number like 100, the zeros might or might not be significant depending on additional information provided.
In conclusion, when counting digits in a number absent of a decimal point, you start from the right side. The final correct option is 2) Right side.