What cr@p. The goal of estimation, as used in business and engineering, is to estimate as closely as possible to the correct answer with the least effort. If the actual correct answer is available with the least effort, THAT IS THE BEST ESTIMATE. The teacher in this case simply does not understand the concept. Estimation is about using the simplest process to arrive at the estimate. Multiplying 9 x 9 is the simplest process and therefore the best estimate. Scaling 9 to 10 and multiplying 10 x 10 takes more steps and is therefore a poor estimate.
In other words, the teacher is not intelligent enough to understand what he/she is supposed to be teaching. Unfortunately, understanding the subject matter is no longer the most important requirement in the primary education profession. Towing the leftist/NEA line is far more important.
That's why I said that the 9x9 example is a very poor choice for teaching estimation. A much better example would have included several more numbers and other operations along with the multiplication. The answer would then be calculated and compared to the estimate.
If the actual correct answer is available with the least effort, THAT IS THE BEST ESTIMATE. The teacher in this case simply does not understand the concept. Estimation is about using the simplest process to arrive at the estimate. Multiplying 9 x 9 is the simplest process and therefore the best estimate.
That process isn't available for kids who haven't memorized their multiplication tables. You and I don't really multiply 9 times 9. We know that the answer is 81 because we once memorized it.
In other words, the teacher is not intelligent enough to understand what he/she is supposed to be teaching. Unfortunately, understanding the subject matter is no longer the most important requirement in the primary education profession.
I don't disagree with that thought at all.
Two possibilities that I see are: 1) As you say, the teacher really doesn't understand what she's teaching. or 2) This was the introduction of the topic to her class and she used too simple a problem for the example.
Towing the leftist/NEA line is far more important.
Truth-in-labeling laws should require the NEA to rename itself the National Teachers' Union.
Exactly. If the numbers are known, it is not an estimate. “Estimate” implies unknowns. If 9x9 is not the exact set of numbers, someone already “estimated” them.