to make any of those numbers from 00.00 to 99.99 we have 10 000 possibles combinations to form a four-digit number.
so if i aim to roll between [00.00 to 49.99] i have 10000/2= 5 000 possibles combinations, so it's 5000/10000=1/2 means that there are only 5000 rolls who can be on [00.00 to 49.99] and the 5000 rest rolls not there. so the probability here is 1/2=0.5=50%
what if i aim [89,99 to 99.99] ? it's quite simple, it's 1000 combinations to do so 1000/10000= 1/10 so the probability is 1/10=0.1=10%
what's about 1% ? yes, you got it correct it's [98.99 to 99.99] means 100 possibles combinations so 100/10000 = 1/100 so the probability here is 1/100= 0.01= 1%
feel free to comment, good luck