Inverse Property of Addition
Inverse property of addition:
$$$\color{purple}{a+\left(-a\right)=\left(-a\right)+a=0}$$$
$$$-a$$$ is called the additive inverse of $$${a}$$$.
Inverse property is true for any real number $$${a}$$$.
Notice, that we wrote, that $$${a}+{\left(-{a}\right)}={\left(-{a}\right)}+{a}$$$. This is true, according to the commutative property of addition.
Example 1. Additive inverse of $$$\frac{{5}}{{3}}$$$ is $$$-\frac{{5}}{{3}}$$$, because $$$\frac{{5}}{{3}}+{\left(-\frac{{5}}{{3}}\right)}={0}$$$.
Example 2. Additive inverse of $$$-\sqrt{{{2}}}$$$ is $$$\sqrt{{{2}}}$$$, because $$${\left(-\sqrt{{{2}}}\right)}+\sqrt{{{2}}}={0}$$$.
Example 3. $$${2.57}+{\left(-{2.57}\right)}={\left(-{2.57}\right)}+{2.57}={0}$$$.
Conclusion. Additive inverse of the number $$$a$$$ is a number, that has the same value as $$${a}$$$, but different sign, i.e. $$$-a$$$.