50000 = 5*10000 = 5*10^4
when you have a number like 10000 or 100, that number is a power of ten, so you can write it like 10^n, where n is the number of zeros after the 1
that means:
1000 = 10^3
10 = 10^1
1 = 10^0 (but it would be silly to write it like that. just write 1. lol)
so yeah, back to the original question, we take 50000 and show it as 5*10000 so we can write 10000 with exponents. 10000 has 4 zeros so 10^4. 5*10000=5*10^4
