Puzzles - Number puzzles

253.
Answer
:
89
Explanation
:
Working from top to bottom, numbers represent the sequence of Square Numbers, from 144 to 289, with the first digit left out.

254.
Answer
:
8
Explanation
:
In each row, the middle value equals the sum of the left and right hand values, adding 2 for the top row, 4 for the middle row, and 6 for the bottom row.

255.
Answer
:
38
Explanation
:
Starting at the top, add 4 to the first number to get the second, then add 5, 6, 7 etc.