This is an example of the "commutative" property.
commutative property of addition
Associative Property of Multiplication
It is the additive property of equality, as the additive property of length, as applied to adjacent or parallel line segments.
I don't know what a 'mathematical' sentence is. I'd prefer to call it an English sentence that describes a mathematical process and makes a statement concerning mathematical matters.
The mathematical statement 31 plus 21 equals 52 as a total.
It is the property that equals plus equals are equals.
This is an example of the "commutative" property.
Addition is commutative.
commutative property of addition
Substitution property.
Associative Property of Multiplication
It is the additive property of equality, as the additive property of length, as applied to adjacent or parallel line segments.
because its zero
I don't know what a 'mathematical' sentence is. I'd prefer to call it an English sentence that describes a mathematical process and makes a statement concerning mathematical matters.
It is the property of commutativity.
It is the additive identity property of zero. For any value, a + 0 = a.