在GRE数学考试中，一般都假定以下信息为真：
●All numbers used are real numbers;
●All figures lie on a plane unless otherwise indicated;
●All angle measures are positive;
●All lines shown as straight are straight. On the computer-based test， lines that appear“jagged" can also be assumed to be straight (lines can look somewhat jagged on the computer screen)：
●Figures are intended to provide useful information for answering the questions. However，except where a figure is accompanied by a“Note" stating that the figure is drawn tO scale， solve the problem using your knowledge of mathematics， not by visual measurement or estimation.
细心的读者会发现，上述假设实际上就是ETS 出题原则，即：
●所有的数都是实数;
●除非GRE数学题目中专门指出假设所有图形都在同一个平面内;
●所有的角的测量值都是正数;
●所有显示为直线的线均可当作直线来处理(在机试中，因为电脑显示器的原因，直线可能会看起来呈“锯齿状”);
●伴随问题的图形将为解题提供有用的信息。但是，只有在GRE数学的问题中指出本图形是按比例画出(drawn to scale)时，才可以用目测或估计而得到的信息去解题。否则，只能运用你的数学知识去回答问题。这一解题原则可以简称为“只能读图，不能度量”的原则。