Cell Value = TextBox1.Value + TextBox2.Value

Good day,
I know this should be as simple but I'm a little lost here.

I have a userform that has two Textbox.
TextBox1 = a calendar popup that will insert the date in Textbox1
Textbox2 = a simple "numberonly" format that the user will enter.

Example: TextBox1 will = to 2013-07-24 and TextBox2 will = to let's say "2"

I need that when I click on my "Add" form button to Calculate Textbox1 (Date) = TextBox2 (number)

Therefore the final result in my Sheet cell will equal to 2013-07-26

This is my Code in my userform:

Cells(ActiveCell.Row + 1, "V").Value = (TextBox4.Value) + (TextBox5.Value)

The output I am getting is the following:

Cells(ActiveCell.Row + 1, "V").Value = 2013-07-24+2

What Am I doing wrong?

What would be an alternative approach?

YES NORIE,
Thank you so Much.