The subtraction principle of equality states that if the same number is added to both sides of an equation, the sides remain equal and the equation remains balanced.
Therefore, if we have an equation such as:
a + b = c
We can subtract the same number from both sides, and the equation will still be true:
(a + b) - b = c - b
a = c - b
This principle allows us to manipulate equations and solve for unknown variables by performing operations on both sides of the equation.