What does the small number above a number mean? the exponent thing?

It's basically saying how many times that number is multiplied by itself

ex:

2²= 2×2

2³= 2×2×2

It means that you take the number and multiply it by itself the amount of what the small number is. for example, if i have 7 with a 2 above it i need to multiply it by itself twice so 

7x7=49

if it has a three above it i need to multiply it by itself 3 times 

7x7x7= 343

hope this helps and feel free to ask further questions

Same length is comparing because it’s saying its the same and not different