import bpy
from random import randint #We need something to generate random numbers with

def random_numbers(scene):
    card_number=''
    #card number reset to empty string

    if (scene.frame_current%5==0):
    #every 5th frame could be every frame number that has no reminder after dividing by 5

        for group_of_4 in range(0,4):
        #we need to do it 4 times so let's use a loop instead of typing

            card_number += str(randint(0,9999)).zfill(4) + ' '
            #zfill is for leading zeros

        bpy.data.objects['Text'].data.body = card_number
        #let's write the text to the text object

bpy.app.handlers.frame_change_pre.append(random_numbers)