Final answer:
Greek mathematicians approximated irrational numbers as fractions.
Step-by-step explanation:
Greek mathematicians did not ignore irrational numbers (a) but instead, they approximated them as fractions (b). They were aware of the existence of irrational numbers and tried to find rational approximations for them. For example, the Greek mathematician Archimedes derived an approximation for the constant pi, which is an irrational number. He expressed it differently, as decimal fractions did not appear in Europe until much later.