- Sloping or joining something at an angle that is not a right angle.
- Neither perpendicular nor parallel to another line or plane.
Having the shape of or resembling a rectangle or ellipse.
obtuse angle 钝角
An angle greater than 90° and less than 180°.
obtuse triangle 钝角三角形
A triangle with one obtuse angle.
A polygon with eight sides and eight angles.
A polyhedron with eight faces.
- Not divisible by two.
- Changing sign but not absolute value when the sign of the independent variable is changed, as in y = x3.
odd number 奇数
Designating an integer not divisible by two, such as 1, 3, and 5.
An instrument that indicates distance traveled by a vehicle.
open sentence 开命题,真伪未定的命题
An expression that contains at least one unknown quantity and becomes true or false when a test value is substituted for the unknown.
A process or action, such as addition, substitution, transposition, or differentiation, performed in a specified sequence and in accordance with specific rules.
A symbol for expressing a mathematical operation.Such as +, -, ×,÷
order of operations 操作顺序
ordered pair 有序对
ordinal number 序数词