For any numbers \(a\), \(b\), and \(c\),
if
$$\large{a = b}$$
and
$$\large{b = c}$$
then
$$\large{a=c}$$
In words: If one element is equal to a second element, and the second element is equal to a third element, then the first element is equal to the third element.
Examples:
If \(2 + 8 = 6 + 4\) and \(6 + 4 = 10\), then \(2 + 8 = 10\)
If \(x + y = a - b\) and \(a - b = {m^2}\), then \(x + y = {m^2}\)