17．Maths
常用句子
The simplest real numbers are the natural numbers，which are just the ordinary counting
number l，2，3…
最简单的真数是自然数，即平时我们口数的一、二、三…。
One convenient way to visualize the real numbers is by the way of a number line．
将真数形象化的最方便的途径是通过数轴。
The numberπis sometimes approximated by the rational number 22／7。
圆周率π约等于22／7。
Rational numbers and irrational numbers together form the set of real numbers．
有理数与无理数一起构成实数。
In mathematics the symbol A = B means A and B are two names for the same thing．
在数学中A = B 意思是A、B 是同一事物的两个名称。
I become headache with maths problems．
考试用书我一解数学题就头痛。
A right angle is an angle of 90°，and a straight angle is one of 180°。
直角是90°角，平角是180°角。
Why do we always have maths in the fourth period？
为什么我们总在第四节课上数学？
