Does not contain a method named 'op_Addition'

function GetServers{
    param(
    $Exceptions
    )
 
    
    # Get all servers. Exceptions will not be selected
    $servers = Get-ADComputer -SearchBase "OU=Servers, DC=domain, DC=com" -Filter {(enabled -eq "true")} | foreach-object { 
        $check = 0
        foreach($Exception in $Exceptions)
            {
            if($_.name -like $exception)
                {
                    $check = 1
                    break;
                }
            }
            if($check -eq 0)
            {
                 $_
            }
        
        }
 
    # add all DCs to $servers array
    Get-ADComputer -SearchBase "OU=Domain Controllers, DC=domain, DC=com" -Filter {(enabled -eq "true")} | ForEach-Object {$servers += $_}
    return $servers
 
}
 
Function GetGroupMembers{
 
    param(
    $GroupName
    )
 
    return $(Get-ADGroupMember $GroupName)
}
function GetSertversToAddToGroup{
    
    param(
    $Servers,
    $GroupMembers
 
    )
    $serversToBeAdded = $null
 
    foreach($Server in $Servers)
    {
    $check = 0
        foreach($GroupMember in $GroupMembers)
        {
            if($server.Name -like $GroupMember.name)
            {
                $check = 1
                break;
            }
        }
        if($check -eq 0)
        {
            $serversToBeAdded += $Server
        }
    }
    return $serversToBeAdded
 
}
 
function GetSertversToDeleteFromGroup{
    
    param(
    $Servers,
    $GroupMembers
 
    )
    $serversToBeDeleted = $null
    foreach($GroupMember in $GroupMembers)
    {
    $check = 0
        foreach ($Server in $Servers)
        {
            if($GroupMember.name -like $Server.name)
            {
                $check = 1
                break;
            }
        }
        if($check -eq 0)
        {
            $serversToBeDeleted += $GroupMember
        }
    }
    return $serversToBeDeleted
 
}
 
function DeleteServersFromGroup{
    
    param(
    $ServersToDeleteFromGroup,
    $GroupName
 
    )
 
        Remove-ADGroupMember -Identity $GroupName -Members $ServersToDeleteFromGroup
 
}
 
function AddServersToGroup{
    
    param(
    $ServersToAddToGroup,
    $GroupName
 
    )
    Add-ADGroupMember -Identity $GroupName -Members $ServersToAddToGroup
 
}
function AddServersToGCentralLoggingGroup{
    
    param(
    # add all exceptions here
    $Exceptions,
    $GroupName
 
    )
    $Servers = GetServers -Exceptions $Exceptions
    $GroupMembers = GetGroupMembers -GroupName $GroupName
    $ServersToAddToGroup  = GetSertversToAddToGroup -Servers $Servers -GroupMembers $GroupMembers
    $ServersToDeleteFromGroup = GetSertversToDeleteFromGroup -Servers $Servers -GroupMembers $GroupMembers
    DeleteServersFromGroup -ServersToDeleteFromGroup $ServersToDeleteFromGroup 
    AddServersToGroup -ServersToAddToGroup $ServersToAddToGroup 
    
 
 
}
 
AddServersToGCentralLoggingGroup -Exceptions "*Linux*", "*svc*", "*000*" -GroupName TEST_GROUP

DeleteServersFromGroup -ServersToDeleteFromGroup $ServersToDeleteFromGroup "Имя группы" 
    AddServersToGroup -ServersToAddToGroup $ServersToAddToGroup "Имя группы"