This page is part of my unofficial solutions manual to the GRE Paper Practice Book (2e), a free resource available on the ETS website. They publish the questions; I explain the answers. If you haven’t worked through the Practice Book, give Section 6 a shot before reading this!

6.16: A Slight Miscalculation

To solve this problem, we need to understand what effect Chris’s mistake had on the result of his calculation. 2,073, the factor that Chris entered into his calculator, is 1,000 times the intended factor of 2.073. So the product will be 1,000 times too large. Consequently, the correct answers will be operations that make the product smaller.

Of the four answer choices, only (A) (“multiply by 0.001”) and (D) (“divide by 1,000”) meet this criterion: either operation would cancel out the erroneous factor of 1,000. Answers (B) and (D) actually make the product even larger, amplifying the original error.

Math Review Reference

For more on this topic, see the following section of the GRE Math Review:

• 1.5: Real Numbers (pp. 7-8)