<p>Look, this was a multiple choice test. She was given four or five possible answers and she had to pick the best one. She didn’t need Newton’s method. All she needed was to know what a square root is, and how to multiply two numbers. Obviously the answer is between 9 (the square root of 81) and 10 (the square root of 100). If there were several answers that looked plausible, all she had to do was square each one, and see which one was closest. </p>
<p>Square roots and multiplication are not arcane mathematical concepts. She should know them. If she doesn’t, she isn’t remotely ready for calculus.</p>