The first step a math tutor would suggest 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:
87 x 87 x 87 x 87 x ... (for a total of 90 times) = 3603568116041180859586897446140385473392059295330132748665924877675152271376814019767345821026697799199446764816758285575259639428115741227261744258286607506123117709174509649
Therefore, 87 to the power of 90 is 3603568116041180859586897446140385473392059295330132748665924877675152271376814019767345821026697799199446764816758285575259639428115741227261744258286607506123117709174509649.

