1. **Stating the problem:** We need to find the number of significant figures (s.f.) for each number in the first table. 2. **Rules for counting significant figures:** - All non-zero digits are significant. - Zeros between non-zero digits are significant. - Leading zeros are not significant. - Trailing zeros in a decimal number are significant. - Trailing zeros in a whole number without a decimal point are ambiguous and usually not significant unless specified. 3. **Counting significant figures for each number:** - 45,631: 5 (given) - 17: Both digits are non-zero, so 2 s.f. - 6,461.67: All digits including decimal part count, so 6 s.f. - 505: Zero between non-zero digits counts, so 3 s.f. - 7,000,003: All digits including zeros between non-zero digits count, so 7 s.f. - 0.0004: 1 (given) - 500,000: Trailing zeros without decimal are ambiguous, assume 1 s.f. - 800.0: Decimal point and trailing zero count, so 4 s.f. - 30300: Trailing zeros without decimal, assume 3 s.f. - 900.87540: All digits including trailing zeros after decimal count, so 8 s.f. **Final answers for significant figures:** | Number | # of Significant Figures | |----------|--------------------------| | 45,631 | 5 | | 17 | 2 | | 6,461.67 | 6 | | 505 | 3 | | 7,000,003| 7 | | 0.0004 | 1 | | 500,000 | 1 | | 800.0 | 4 | | 30300 | 3 | | 900.87540| 8 |