The missing value is approximately **20**.
To find the missing value in the estimation 82 x 19 ≈ 80 x ?, we can use approximation and try to balance the adjustments made:
- 82 is rounded down to 80, so we need to increase the other factor slightly to compensate.
- 19 is close to 20, so we can use that as a starting point.
Considering these adjustments, we can estimate:
82 x 19 ≈ 80 x 20
Therefore, the missing value is approximately **20**.
The probable question may be:
Work out the missing value in the estimation below
82 x 19 ≈ 80 x ?