Brain Teasers and Puzzles 

Workings

Hint
There are twelve items in the full sequence.

Answer
Jly.

From the months with their vowels removed. January, February, March, April, May, June, July.

Workings

Hint
Loot at each number backwards.

Answer
32.

The first prime numbers reversed.

Workings

Hint
This is quite a common list.

Answer
T.

The first letters of playing cards in descending order of value.

Workings

Hint
This is a well known nursery rhyme.

Answer
HDD.

The initial letters from the nursery rhyme, Hickory Dickory Dock.
Hickory, dickory, dock,
The mouse ran up the clock,
The clock struck one,
The mouse ran down,
Hickory, dickory, dock.