Select and add excel values

I am wanting to create a script that would basically add the sum of what is in excel and save it as a variable so i can input it somewhere else.

Excel looks like this:

Count Store_Name
5 Store 1
10 Store 2
5 Store 3
So i would just need to add everything in column A and store it in a variable (5+10+5) = 20, $Count = 20

$filePath ="E:\Extra\Note\Test.xlsx"
$excelObj = New-Object -ComObject Excel.Application
$excelObj.Visible = $false

#open WorkBook
$workBook = $excelObj.Workbooks.Open($filePath)
$workSheet = $workBook.sheets.Item(1)

#Select the range of rows should read
$range= 1
for($i=1;$i-le $range;$i++){

This is what i have learned so far, but im sure there are better ways than me copying $worksheet.Range ("A1").Textfor the whole column until 300, and then trying to find out how to add them together.

You could use the fantastic ImportExcel module, then use Import-Excel cmdlet to import the xlsx file.
then use Measure-Object cmdlet to calculate the sum of any property.

Import-Excel -Path c:\temp\test.xlsx | Measure-Object -Property count -Sum