1) AZ, GT, MN, _, YB, find the missing letters.
1) KF
2) RX
3) SH
4)
TS

The first letter moves 6 steps forward. The second letter moves 6 steps backwards.

2) AZ, CX, FU, _, find the missing letters.
1) IR
2) IV
3) JQ
4)
KP

The first letter moves 2, 3, 4, .. steps forward. The second letter moves 2, 3, 4, .. steps backwards.

3) Find the missing letters in the series, AZ, BY, CX, _.
1) KF
2) RX
3) SH
4) DW

The first letter moves 1 step forward. The second letter moves 1 step backwards.

4. Find the missing letters in the series, _, SIY, OEU, KAQ, GWM, CSI.
1) WNE
2) WNB
3) WNE
4)
WMC

The letters move 4 steps backwards to obtain the next term.

5) Find the missing letters in the series, DKY, FJW, HIU, JHS, _ .
1) KGR
2) LFQ
3) KFR
4)
LGQ

The first letter moves 2 steps forward. The second letter moves 1 step backwards. The third letter moves 2 steps backwards.

6) CMW, HRB, _, RBL, WGQ, BLV, find the missing letters.
1) MWG
2) LVF
3) LWG
4)
WMX

Each letter moves 5 steps forward.

7) BXJ, ETL, HPN, KLP, _, find the missing letters.
1) NHR
2) MHQ
3) MIP
4)
NIR

The first letter moves 3 steps forward. The second letter moves 4 steps backwards. The third letter moves 2 steps forward.

8) QPO, SRQ, UTS, WVU, _, find the missing letters.
1) XVZ
2) ZYA
3) YXW
4)
VWX

The first letter and the last letter of the next term are the same. Each term consists of three consecutive letters in reverse order.

9) JE, LH, OL, SQ, _, find the missing letters.
1) WV
2) WX
3) VW
4)
XW

The first letter moves 2, 3, 4, .. steps forward. The second letter moves  3, 4, 5, .. steps forward.

10) AD, EH, IL, _, QT, find the missing letters.
1) LM
2) MN
3) IL
4)
QT