Scratch

I teach an after school activity on computer programming for kids in grades 3 to 5 using Scratch. I want to know if there is an upper limit on the values that can be entered in the input areas. I also want to know if there is a maximum number for the sprites that  can be included in a project.

When I introduce the move block to the students and tell them that they can change the value in the white area, immediately I get asked the following questions: Can I enter a million? How about a billion? and so on.

I decided to do a little experiment. I painted a dot for sprite and I put together the following blocks
[blocks]<go to x   0 )y   0
<move(  )steps> [/blocks]
I increased the number of steps from 10 to 100 to 1000 and so on and ran the script. I monitored the x position each time and here's what I got
After [blocks]<move(10  )steps> [/blocks] x position was 10
[blocks]<move(100  )steps> [/blocks] x position was 100
[blocks]<move(1000  )steps> [/blocks] x position was 240
[blocks]<move(10000  )steps> [/blocks] x position was 240
and so on till the number of steps was 1 followed by 16 zeroes. The sprite was visible on the stage.
When I increased the steps to 1 followed by 17 zeroes, the x position changed to 234, and the sprite became invisible. The x position kept changing with the number of zeroes
For 1 followed by 18 zeroes, x position was 250
For 1 followed by 19 zeroes, x position was -774
For 1 followed by 20 zeroes, x position was -774
This kept on as I added more zeroes.
Can someone explain why this is happening?

I also tried putting the move block inside the forever as below. I used the butterfly1-a sprite from animals folder for this code.
[blocks]<when green flag clicked>
<forever>
    <move(  )steps>
    <if on edge, bounce>
[/blocks]
end<forever>
When the number of steps was less, the y position remained constant. When the number of steps was increased to 1 followed by 14 zeroes, the y position started changing with the bounce. In other words, the sprite kept sliding down when it bounced.
Can someone also explain why this is happening?
My 8 year old son saw this project and named it "why y butterfly"

My next question is whether there is a limit on the number of sprites that can be put in a project. Please let me know.

Thanks