The expression a^(m-m) simplifies to a^0 because m - m equals zero. In mathematics, any non-zero number raised to the power of zero is defined to be one. Therefore, regardless of the value of a , as long as a ≠ 0 , the expression evaluates to 1. This property is part of the rules of exponents, which are fundamental in algebra. The rule states that a^n divided by a^n equals a^(n-n) , reinforcing that any number to the power of zero is one. This concept is crucial in various fields, including calculus and computer science.