The theoretical probability is what is expected based on using math. Since there is only one card that is number 1, and there are 400 possible outcomes, then the theoretical probability is 1/400 which is 0.25%.
Now find the experimental probability by find the number of times card 1 is picked, and the number of cards in total. 128/400 = 0.32 which is 32 percent.
The experimental probability is higher than the theoretical probability.
Hope this helps