An unknown equation. It is an equation that represents the equal relationship between two mathematical expressions (such as two numbers, functions, quantities and operations), and the value of the unknown quantity that makes the equation hold is called "solution" or "root". An equation must be an equation, and an equation is not necessarily an equation. An equation without unknowns is not an equation.
Relationship between equality and equality
Use the previous symbols to move some items in the equation from one side to the other, and add, subtract, multiply, divide, multiply and divide. Both sides of the equation are multiplied or divided by the same non-zero number at the same time, and the result is still an equation.
An equation must be an equation, but an equation is not necessarily an equation.
Example: a+b= 13 conforms to the equation, and there are unknowns. This is an equation and an equation.
1+ 1=2 , 100× 100= 10000。 These two formulas are consistent with the equation, but there are no unknowns, so they are not equations.
In the definition, the equation must be an equation, but there can be other equations, such as 1+ 1 = 2,100×10000 =10000, all of which are equations. Obviously, the range of the equation is larger.