1. **State the problem:** We need to perform two calculations and express the answers in meters, applying the rules of significant figures for addition/subtraction and multiplication/division. 2. **Recall the rules:** - For addition/subtraction, round the final answer to the least number of decimal places among the numbers. - For multiplication/division, round the final answer to the least number of significant figures among the numbers. 3. **Problem a: Calculate $0.76\,m + 84\,cm + 2.3\,mm$** - Convert all to meters: - $84\,cm = 0.84\,m$ - $2.3\,mm = 0.0023\,m$ - Sum: $$0.76 + 0.84 + 0.0023 = 1.6023\,m$$ - Decimal places: - $0.76$ has 2 decimal places - $0.84$ has 2 decimal places - $0.0023$ has 4 decimal places - Least decimal places is 2, so round to 2 decimal places: $$1.6023 \to 1.60\,m$$ 4. **Problem b: Calculate $1.84\,km \times 2.7\,m \times 17\,cm$** - Convert all to meters: - $1.84\,km = 1840\,m$ - $2.7\,m$ stays as is - $17\,cm = 0.17\,m$ - Multiply: $$1840 \times 2.7 \times 0.17 = 843.36\,m^3$$ - Count significant figures: - $1.84$ has 3 significant figures - $2.7$ has 2 significant figures - $17$ has 2 significant figures - Least significant figures is 2, so round to 2 significant figures: $$843.36 \to 840\,m^3$$ **Final answers:** - a) $1.60\,m$ - b) $840\,m^3$