Brain Teasers and Puzzles 

Workings

Hint
The word begins with the letter S.

Answer
SWIMS.

Workings

Hint
Think of Roman numerals.

Answer
Delta.

Take the Roman numerals in sequence, and convert to the phonetic alphabet.
  1 = I = India
  5 = V = Victor
 10 = X = X-Ray
 50 = L = Lima
100 = C = Charlie
500 = D = Delta

Workings

Hint
In the first box, look at 7 & 3, and 4 & 1, to see how we can use them to make 12.

Answer
4.

Reasoning
For each row, the left minus the right gives a number.

The numbers for the rows are then multiplied together.

In the first box:

   7 – 3 = 4
   4 – 1 = 3

so 4 x 3 = 12

In the second box:

   9 – 2 = 7
   8 – 3 = 5

so 7 x 5 = 35

In the last box:

   6 – 2 = 4
   8 – 7 = 1

so 4 x 1 = 4.

Workings

Hint
The missing word is in these locations: lo---e, ---ch, s---he, ---er, va---e.

Answer
Cat.
loe  = locate ch   = catch she  = scathe er   = cater vae  = vacate