“因为”的符号：∵“所以”的符号：∴。
= 等于 is equal to
≠ 不等于 is not equal to
≈ 约等于 approximately equal to
< 小于 is less than
> 大于 is greater than
// 平行 is parallel to
⊥垂直
≥ 大于或等于 is greater than or equal to
≤ 小于或等于 is less than or equal to
≡ 恒等于或同余。
