Solution:

yaM

Explanation:
voN luJ ? raM beF

Step-1: Reversing the input text gives us:
Feb Mar ? Jul Nov

Step-2: Replace by month numbers
2 3 ? 7 11

Step-3: Find the relation
They all are prime numbers, the missing number here is "5".

Step-4:
5th month is May and reverse of May is yaM (answer)

Solution:

A

Explanation:
Pi = 3.141592653.....
All images are related by pi value i.e "The number of straight lines on each shape corresponds to the digits of pi."

Solution:

21982030

Explanation:
Next number formed is (number * (number-2)) - number;
i.e
(5 * 3) - 5 => 10
(10 * 8) - 10 => 70
(70 * 68) - 70 => 4690
(4690 * 4688) - 4690 => 21982030

Solution:

TH

Explanation:
1st 2nd 3rd 4th 5th

Solution:

121

Explanation
Tables consist of squares of the number from 4 to 12.
11^2 = 121.

Solution:

2003.

Explanation:
Its a series of prime numbes.

Solution:

O

Explanation :
6 + 6 + 6 = N (last letter of sum i.e. eighteen)
7 + 7 + 7 = E (last letter of sum i.e twentyone)
8 + 8 + 8 = R(last letter of sum i.e twentyfour)
Therfore
0 + 0 + 0 = O (last letter of sum i.e. zero)

Solution:

See the picture for the answer. Don't worry if you have a different answer; this question can be solved with different numbers. However, do post your answer in the comments.

Solution:

118119

Explanation:
Number are generated as below
1 2
3 4
1 x 4 + 2 = 6 , 2 x 3 + 1 = 7 => 67

3 4
5 6
3 x 6 + 4 = 22, 4 x 5 + 3 = 23 = 2223

5 6
7 8
5 x 8 + 6 = 46, 6 x 7 + 5 = 47 = 4647

7 8
9 10
7 x 10 + 8 , 8 x 9 +7 = 7879

Based on above pattern, desired number will be calculated as :
9 10
11 12
9 x 12 + 10 = 118, 10 x 11 + 9 = 119 = 118119

Solution:

'T'

Explanation:
The letters around the center are actually depending on the letter in the center. They are advancing according to the numerical value of that letter.

For example, F, G, H and I are advancing by 1 because the center letter is A, which has the numerical value 1.

Again, G, K, S, and O are advancing by 4, because the center letter is D, which has a numerical value of 4.

Similarly, N has advanced by 6 from H, because the center letter is F, which has a numerical value of 6. Hence, the missing letter should be T.