Solution:

276

6 = 11 + 21 + 31
14 = 12 + 22 + 32
36 = 13 + 23 + 33
98 = 14 + 24 + 34
276 = 15 + 25 + 35

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:

1806

each number is multiplied by the number+1
1x2 = 2
2x3 = 6
6x7 = 42
42x43 = 1806
1806x1807 = 3263442

Solution:

The answer is 1

6 {6^1}
25 {5^2}
64 {4^3}
81 {3^4}
32 {2^5}
1 {1^6}

Solution:

4

92 - 38 = 54
5 is given and 4 is missing

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:

-20

Its a alternate series riddle
60 40 20 0 (?)
40 43 46 49 (+3)

Solution:

6

sum of opposite number is 21

Solution:

245

space them properly as 21 24 27 30 33 36 39 42 45 ?

Solution:

4

6*3 equals 18
7*9 equals 63
6*4 equals 24
7*6 equals 42, ? should be replaced by 4.