The first step is to understand what it means when a number has an exponent. The “power” of a number indicates how many times the base would be multiplied by itself to reach the correct value.
The second step is to write the number in the base-exponent form, and lastly calculate what the final result would be. Consider the example of 2 to the power of 4: in exponent form that would be
So re-applying these steps to our particular problem, we first convert our word problem to a base-exponent form of:
To simplify this, all that is needed is to multiply it out:
15 x 15 x 15 x 15 x ... (for a total of 90 times) = 7050392822843069367725353867951204442321414418661736485822774515332123090871618842356838285923004150390625
Therefore, 15 to the power of 90 is 7050392822843069367725353867951204442321414418661736485822774515332123090871618842356838285923004150390625.