You have to follow the laws of exponents. For exponents as integers, the law that are applicable for simplification are the following:
1. If the two algebraic or numeric terms has the same base, you can add their exponents.
Ex: a² + a³ = a²⁺³ = a⁵ or 6² + 6⁵ = 6⁷
2. When an exponent is outside a base raised to another exponent, simply multiple the exponents:
Ex: (a²)³ = a⁶
3. If you divide two terms with the same bases, just subtract the exponent of the numerator to the denominator.
Ex: a³/a² = a³⁻² = a¹ or a
4. When any base is raised to the power of zero, the answer is 1.
Ex: 100,000⁰ = 1
5. If the integer exponent is negative, take the reciprocal to make the exponent positive.
Ex: a⁻³ = 1/a³