Compare two DataTables and Delete the Matched Records and bi

Question

i am creating online exam application now i want Compare two DataTables and Delete the Matched Records and bind the Remaining Data on GridView using c#

i have two tables
1.TestSeries
2.TestCompleted
in my TestSeries table i have the following records
1.Test Series 01
2.Test Series 02
3.Test Series 03
4.Test Series 04
5.Test Series 05
6.Test Series 06
7.Test Series 07
8.Test Series 08
9.Test Series 09
10.Test Series 10
and my TestCompleted table have the following Records
1.Test Series 01
2.Test Series 02
3.Test Series 03
my expected output is like this
1.Test Series 01
2.Test Series 02
3.Test Series 03
4.Test Series 04
5.Test Series 05
6.Test Series 06
7.Test Series 07

if anyone how to do this na suggest me