1. **State the problem:** We need to convert the volume of a cube from cubic centimeters (cm³) to cubic millimeters (mm³). 2. **Given:** The volume of the cube is 125 cm³. 3. **Formula and conversion rule:** - 1 cm = 10 mm - Therefore, to convert cubic centimeters to cubic millimeters, we cube the conversion factor: $$1\ \text{cm}^3 = (10\ \text{mm})^3 = 10^3\ \text{mm}^3 = 1000\ \text{mm}^3$$ 4. **Convert the volume:** $$125\ \text{cm}^3 = 125 \times 1000\ \text{mm}^3$$ 5. **Calculate:** $$125 \times 1000 = 125000$$ 6. **Final answer:** $$125\ \text{cm}^3 = 125000\ \text{mm}^3$$ So, the volume in cubic millimeters is 125000 mm³.