An algebraic symbol which appears with a minus sign is called a negative algebraic symbol.
Quantities are expressed in terms of letters in algebraic system but some algebraic symbols are appeared with negative sign. There is a scientific reason for it.
In universe, there is a natural system to happen or do everything. The direction of natural system is considered as positive direction and the opposite direction is known as negative direction. It is expressed by a minus sign ().
If something is happened or done in opposite to the natural system, it is expressed by a negative sign. Due to this reason, the algebraic symbols are appeared with negative sign in mathematics.
A girl stood on the floor to know her height and it is measured that her height is centimetres. The quantity is a number and represents her height in mathematics.
We are all living on the surface of the earth and everything should be on it. Therefore, the surface of the earth is considered as base to measure the heights and this method is natural scientifically.
Due to this reason, heights are measured from the surface of the earth to top of the object. If height is measured in reverse direction, it is known as negativity of actual measuring system. The negativity is expressed by a minus () sign and it is displayed before to the quantity.
In this case, the height of the girl is measured from top of her head to surface of the floor. This is opposite direction to the natural measuring system. Hence, a negative sign is displayed before to her height. It means her height is centimetres.
Assume, the absolute value of her height is represented by an alphabetic letter and therefore .
The height is measured opposite to the natural system. So, the height is written by displaying a negative sign. Now the height of the girl is written as in mathematics.
The algebraic symbol is having a minus sign to represent a quantity. So, the algebraic symbol is called a negative algebraic symbol in mathematics.