1. **State the problem:** We need to find the combined mass of Earth and Venus by performing addition, subtraction, multiplication, and division on their masses. 2. **Given data:** - Mass of Earth $= 5.9 \times 10^{24}$ kg - Mass of Venus $= 4.9 \times 10^{24}$ kg 3. **a) Addition:** $$5.9 \times 10^{24} + 4.9 \times 10^{24} = (5.9 + 4.9) \times 10^{24} = 10.8 \times 10^{24} = 1.08 \times 10^{25}$$ 4. **b) Subtraction:** $$5.9 \times 10^{24} - 4.9 \times 10^{24} = (5.9 - 4.9) \times 10^{24} = 1.0 \times 10^{24}$$ 5. **c) Multiplication:** $$5.9 \times 10^{24} \times 4.9 \times 10^{24} = (5.9 \times 4.9) \times 10^{24+24} = 28.91 \times 10^{48} = 2.891 \times 10^{49}$$ 6. **d) Division:** $$\frac{5.9 \times 10^{24}}{4.9 \times 10^{24}} = \frac{5.9}{4.9} \times \frac{10^{24}}{10^{24}} = \frac{5.9}{4.9} \times \cancel{\frac{10^{24}}{10^{24}}} = 1.204$$ **Final answers:** - Addition: $1.08 \times 10^{25}$ kg - Subtraction: $1.0 \times 10^{24}$ kg - Multiplication: $2.891 \times 10^{49}$ kg$^2$ - Division: $1.204$ (dimensionless)