Make loop run faster

Hi all. I need to see if I can make this loop any faster, but first, I have a question regarding this. I don't know why I did

Dim Temp!, pTemp!, ema!

What does that mean? I just want to know when to use the "!" .. If I define any of those as an Integer or a Long, it rounds the final answer to a whole number...so I have to use the above in order for the loop to work correctly. Why is that?

Anyway, here is the loop. If someone can tell me how to make it run faster, I'd really appreciate that. Thank you!

Sub exp20()

Dim Temp!, pTemp!, ema!

Application.ScreenUpdating = False

LR = Cells(Rows.Count, "A").End(xlUp).Row

EMAp = 10

For i = 2 To LR - EMAp
    
    Temp = 0: pTemp = 0:

    For j = 1 To EMAp
        Temp = Cells(i + j - 1, 7).Value
        pTemp = pTemp + Temp
    Next j
    
    ema = pTemp / EMAp
    
Cells(i, 12).Value = ema

Next i

Application.ScreenUpdating = True