We are asked to determine how many significant figures does the number 2.3 have?
Recall the rules for significant figures,
1. Non-zero digits are significant.
2. Any zeros between two significant digits are also significant.
3. Trailing zeros in the decimal are also significant.
Based on the rule 1, the number 2.3 have two significant figures.
2 is the first significant figure and 3 is the 2nd significant figure since they are non-zero digits.
Therefore, the number 2.3 have two significant figures.