“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。