Try this:
SELECT Qty_Device_ID, sum(Qty_Received)
FROM Tbl_ReceivedQty
WHERE Qty_Date between '2013-07-21' and '2013-07-23'
GROUP BY Qty_Device_ID
SELECT T1.Device_Name, T2.Qty_Device_ID, T2.Qty_User, T2.Qty_Date, SUM(T3.Qty_Received) AS SubTotal
FROM Tbl_Device AS T1 INNER JOIN Tbl_ReceivedQty AS T2 ON T1.Device_ID = T2.Qty_Device_ID
INNER JOIN Tbl_ReceivedQty AS T3 ON T1.Qty_Device_ID = T3.Qty_Device_ID
WHERE Qty_Date BETWEEN '2013-07-21' AND '2013-07-23'
GROUP BY T1.Device_Name, T2.Qty_Device_ID, T2.Qty_User, T2.Qty_Date