Solution:

180

2 + 2 = 4 {2 * 2 * 1}
3 + 3 = 18 {3 * 3 * 2}
4 + 4 = 48 {4 * 4 * 3}
6 + 6 = 180 {6 * 6 * 5}

Solution:

To make things easier, let us just denote each box with the help of R number and C number i.e. the row number and the column number.

The rule that has been used here is:
R4C1 = (R1C1 * R3C1) - R2C1 = (5 * 2) - 8 = 2
R4C2 = (R1C2 * R3C2) - R2C2 = (7 * 4) - 10 = 18
R4C3 = (R1C3 * R3C3) - R2C3 = (6 * 5) - 12 = 18

Using the same rule for the last box:
R4C4 = (R1C4 * R3C4) - R2C4 = (4 * 9) - 17 = 19

Thus 19 is the missing number.

Solution:

181

Explanation:
+11 =>16
+33 =>49
+55 =>104
+77 =>181

Solution:

22

Its is sequence of prime numbers and adding 5 to theb number

As we know, 1st seven Prime numbers are :
2 , 3 , 5 , 7 , 11 , 13 , 17

Adding 5 to each number =>
7 , 8 , 10 , 12 , 16 , 18 , 22(Ans)

Solution:

If you look closely, you will find a sequence in every alternating number.
192, 222 and 252 form one series where 30 is added each time.
021, 324 and 627 form one series where 303 is added each time.

Thus the next two numbers will be 282 and 930.

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:

52

sum of consecutive prime numbers
(2+3 , 5+7 , 11+13 , 17+19 , 23+29)

Solution:

240

40 { diff 20 + 12 =>32 add to it}
72 { diff 32 + 12 =>44 add to it}
116 { diff 44 + 12 =>56 add to it}
172 { diff 56 + 12 =>68 add to it}
240

Solution:

-20

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

Solution:

The answer is 1

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