Populate a list based on a single cell

Hi, I am helping my son with the display of a quadratic in Excel. I won't go into detail about what he is required to do but essentially I would like to do the following:

When I enter a value for 'Number of Steps' from a drop down a table is generated with the x values changing accordingly.

For example:

Number of Steps 5

x x^2
------------
0 0
1 1
2 4
3 9
4 16

Number of Steps 9

x x^2
------------
0 0
0.5 0.25
1 1
1.5 2.25
2 4
2.5 6.25
3 9
3.5 12.25
4 16

You will notice that the number of steps is the number of x values that take us up to 4. The 4 is fixed.
I would be able to work out the maths myself as I am a maths teacher but I was wondering how I could autopopulate the table based on a drop down box selection. If it involves going into VBA then don't worry my son needs to get to grips with what I have done.

Hope you can help.
Regards,
David.

Edit. The formatting does not seem to work above.
On the left of each table is supposed to be the x value and on the right is x^2.

Edit: Thanks for the comment. Changed accordingly.