Random Puzzles 

Workings

Hint
There are more than 37, look at the different sizes.

Answer
There are 64 hexagon-type shapes in total.

Reasoning
37 single hexagons
 + 19 hexagons that contain 7 smaller hexagons
 + 7 hexagons that contain 19 smaller hexagons
 + 1 large hexagon that contains all of the smaller hexagons.

Workings

Hint
Something's wrong with the letter O, and the word 'oifoeront' is important to the answer.

Answer
15 different letters: acdefhilmrstvwy.

Reasoning
The sentences should read:

As you can see, my printer replaces every third letter with the letter 'o'.

How many different letters have been replaced?

Workings

Hint
The word begins with the letter S.

Answer
SWIMS.

Workings

Hint
You have to highlight three numbers.

Answer
6 + 1 + 12 = 19.

The puzzle didn't ask for three digits to be highlighted!