Excel vba将值分配给数组，然后粘贴到工作表

I have a very large spreadsheet that I want to do calculations on. In order to speed this up I want to do them in vba. I have a basic knowledge of vba so to start I was trying to write code that would simply copy the cells in column A and assign them to an array and then paste all the values back into another column D. I defined numrows to get the number of rows down as this will be changing from month to month. I thought if I could get this to work I could build it up from there - but unfortunately I can't get this to work. If anyone could tell me what I'm doing wrong I'd really appreciate it. I have a very large spreadsheet that I want to