One of the fundamental problems with learning mathematics is that the number sense may be (i)_____, exact calculation requires cultural tools—symbols and algorithms—that relatively new and must therefore be absorbed by areas of the brain designed for other purpose, which is easier when what we are learning (ii)_____ our built-in circuitry with an understanding of it we can at least (iii)_____ our teaching methods by reflecting on the constraints it imposes.
答案：A,D,I