Run-time error '13': Type mismatch - How to work with Cell.value

Hi, I am new to VBA but have some familiarity with programming.

I am trying to average a set of values based on the date the values were entered for each unique date. I am keeping a count and running total as my program looks through the data for each date that is the same as the previous (then dividing the "running total" by "count") to get the average). I am then trying to output this info in 2 columns - date and average value.

I think the main problem is that I am trying to store the running total in a cell and then do math on it (based on what I could find on the error code given and other forums). But I can't seem to store the cell value in a variable either so I don't know the best practice or work around for this. Full code below, but I think the main problem is these two lines:

Cells(k, 12).Value = Cells(k, 12).Value + Cells(i, 6).Value
...
Cells(k, 12).Value = Cells(k, 12).Value / count

Where k and i are iterative variables for the row.

 Private Sub CommandButton1_Click()
Dim i As Integer
Dim k As Integer
Dim count As Integer

i = 2
k = 2
count = 0


Do While Cells(i, 1).Value <> ""
    If count = 0 Then
        'initial value for a new date
        Cells(k, 11).Value = Cells(i, 1).Value 'Column 1=date stamps, column 6=value; column 11=date, column 12=average
        Cells(k, 12).Value = Cells(i, 6).Value
        count = 1
    Else
        i = i + 1
        'if date is different, begin adding values from column 6 and store them in column 12
        If Cells(i, 1).Value = Cells(k, 11).Value Then
            Cells(k, 12).Value = Cells(k, 12).Value + Cells(i, 6).Value
            count = count + 1
        Else
        'if date is same, calculate average, and increment the place to store date (for average)
            Cells(k, 12).Value = Cells(k, 12).Value / count
            count = 0
            k = k + 1
        End If
    End If
    
Loop
                
End Sub

Thanks!