What is the easiest way to show my 11 year old to simplify fractions?

Consider a cube that has sides of length l. now consider putting the largest sphere you can inside this cube without any point on the sphere lying outside of the cube. the volume ratio -volume of the sphere/ volume of the cube is 1. 5.2 × 10−1 2. 3.8 × 10−1 3. 1.9 4. 2.5 × 10−1 5. 3.8

What is the value of the expression i 0 × i 1 × i 2 × i 3 × i 4? 1 –1 i –i

Aa at 9 a. m. it at 4 p. m. he a of $28.84.?