I assume you mean the product of mixed numbers,
3 1/2 × 3 1/2
If we write this as
(3 + 1/2) × (3 + 1/2) = (3 + 1/2)²
we can use the identity
(a + b)² = a² + 2ab + b²
so that
3 1/2 × 3 1/2 = 3² + (2 × 3 × 1/2) + (1/2)²
3 1/2 × 3 1/2 = 9 + 3 + 1/4
3 1/2 × 3 1/2 = 12 1/4
Alternatively, we can first write 3 1/2 as a mixed number:
3 + 1/2 = 6/2 + 1/2 = (6 + 1)/2 = 7/2
Then
3 1/2 × 3 1/2 = 7/2 × 7/2 = (7 × 7) / (2 × 2) = 49/4
and
49/4 = (48 + 1)/4 = ((4 × 12) + 1)/4 = 12 + 1/4
The first one is (v+6)(v-6)
21. Broooooo, This is baby stuff!
So to find out the answer, you need to find out the dimensions of each cube. So for the 1331, it's 11 x 11 x 11. So you know that would be 11 meters high. Now the next cube. Then there's another 1331, so that would be another 11 meters high. Then 729, also 9 x 9 x 9, so that's going to be 9 meters high. Then add all the cube square roots. 11 + 11 + 9 = 31. So the height of the stacked boxes will be 31 meters.