Solution:

54325

Explanation:

Consider 1 = 5
2 = 25
3 = 325
4 = 4325
Then 5 = 54325

See the pattern. With every digit, the previous numbers are added after that digit

So the next number in the series is 54325

Solution:

9

cube of prime numbers
2*2*2 => 8
3*3*3 => 27 ...Answer
5*5*5 => 125
7*7*7 => 343
11*11*11 =>1331

Solution:

The answer is 0.
As
6 / 7 = 42 but the answer is written as 2
3 / 9 = 27 but the answer is written as 7
8 / 2 = 16 but the answer is written as 6
If we look at the answers, the second digit has been used in the problem.
Now, as
4 / 5 = 20 and the second digit is 0, the answer is 0.

Solution:

6

Explanation:
5*6 + 2 = 31
=> 7*6 + 2 = 44

Solution:

30(sum of corner of triangle)

Solution:

400

Explanation:
Begins with 15
2*15-1 => 29
2*29-2 => 56
2*56-4 => 108
2*108-8 => 208
2*208-16 => 400

Solution:

1113213211


Explanation
1
one one => 11
two one => 21
one two , one one = > 1211
one one , one two , two one => 111221
three one , two two one one => 312211
one three, one one , two two, two one =>13112221

=>one one , one three, two one, three two, one one

Solution:

20 (double of previous)

Solution:

5

(8+7) * 5 => 75

Solution:

43