1. **Stating the problem:** We want to find the area of a big rectangle that is 10 cm by 10 cm and a smaller rectangle inside it that is 6 cm by 5 cm. Then, we find how much space is left in the big rectangle after the smaller one is inside. 2. **Formula for area of a rectangle:** The area is found by multiplying the length by the width: $$\text{Area} = \text{length} \times \text{width}$$ 3. **Calculate the area of the big rectangle:** $$10 \times 10 = 100$$ So, the big rectangle has an area of 100 square centimeters. 4. **Calculate the area of the smaller rectangle:** $$6 \times 5 = 30$$ So, the smaller rectangle has an area of 30 square centimeters. 5. **Find the remaining area:** We subtract the smaller area from the big area: $$100 - 30 = 70$$ 6. **Explanation:** The smaller rectangle takes up 30 square centimeters inside the big rectangle, so the leftover space is 70 square centimeters. **Final answer:** The remaining area inside the big rectangle is $70$ square centimeters.