Just run the program and you'll see how it works
I have changed the program to select a group of multiplication tables by creating a table. It's now configured to ask questions with the multiplication tables of 2, 3, 5 and 10. By adding numbers to the table you add the corresponding multiplication table.
I have also added two counters, one to track how many questions are already answered (disguished as correct answers for the kid) and one to keep track of how many mistakes have been done along the test.
Again I have just modified to set a countdown timer.
20 multiplications in 150 seconds.