If 'P' means '+', 'Q' means 'x', 'R' means '÷' and 'S' means '-', then
44 Q 9 R 12 S 6 Q 4 P 16 =?

Rules
(i) (2-digit even number) ÷ ( Even number)
(ii) (Even number) x (Prime number)
(iii) (Odd number) + (Odd number)
(iv) (3-digit number) - (2-digit perfect square number)
(v) (3-digit number) ÷ (2-digit non-perfect square number)
Solution
1st Row 24   7   81 ? 24 x 7 = 168       [rule (ii)]
?     168 - 81 = 87     [rule (iv)]
        = x
2nd Row x   27   19 ? 87   27   19
?         87 + 27 = 114     [rule (iii)]
?         114 ÷ 19 = 6     [rule (v)]
? Resultant of second row = 6

Rules
(i) (2-digit even number) ÷ ( Even number)
(ii) (Even number) x (Prime number)
(iii) (Odd number) + (Odd number)
(iv) (3-digit number) - (2-digit perfect square number)
(v) (3-digit number) ÷ (2-digit non-perfect square number)
Solution
1st Row 125   64   33 ? 125 - 64 = 61       [rule (iv)]
?     61 + 33 = 94     [rule (iii)]
        = x
2nd Row 282   x   39 ? 282   94   39
?         282 ÷ 94 = 3     [rule (v)]
?         3 + 39 = 42     [rule (iii)]
? Resultant of second row = 42

Rules
(i) (2-digit even number) ÷ ( Even number)
(ii) (Even number) x (Prime number)
(iii) (Odd number) + (Odd number)
(iv) (3-digit number) - (2-digit perfect square number)
(v) (3-digit number) ÷ (2-digit non-perfect square number)
Solution
1st Row 97   45   71 ? 97 + 45 = 142       [rule (iii)]
?     142 ÷ 71 = 2     [rule (v)]
2nd Row 48   8   11 ? 48 ÷ 8 = 6     [rule (i)]
?         6 x 11 = 66   [rule (ii)]
? Required sum = 2 + 66 = 68

Rules
(i) (2-digit even number) ÷ ( Even number)
(ii) (Even number) x (Prime number)
(iii) (Odd number) + (Odd number)
(iv) (3-digit number) - (2-digit perfect square number)
(v) (3-digit number) ÷ (2-digit non-perfect square number)
Solution
1st Row 16   7   25 ? 16 x 7 = 112       [rule (ii)]
?     112 - 25 = 87 = m     [rule (iv)]
2nd Row m   23   22 ? 87   23   22
?         87 + 23 = 110   [rule (iii)]
?       110 ÷ 22 = 5     [rule (v)]
? Resultant of second row = 5

Rules
(i) (2-digit odd number) + (2-digit odd number)
(ii) 2-digit even number ? 2-digit perfect square odd number then, (odd number) - (Even number)
(iii) (3-digit number) ÷ (2-digit number)
(iv) (Prime number) + (Even number)
(v) (Even number) x (Even number)
Solution:
1st Row 12   28   84 ? 12 x 28 = 336     [rule (v)]
?         336 ÷ 84 = 4 [rule (iii)]
2nd Row 37   22   18 ? 37 + 22 = 59     [rule (iv)]
?         59 + 18 = 77 [rule (iv)]
? Required sum = 4 + 77 = 81

Apply All option one by one
5 + 3 x 8 - 12 ÷ 4 = 3
Now, after changing the sign for option C
5 + 3 x 8 ÷ 12 - 4 = 3
Apply the BODMAS Rule
5 + 3 x 8/12 - 4 = 3
5 + 2 - 4 = 3
3 = 3

Given Question is 18 Q 12 P 4 R 5 S 6
After changing the letters in to signs as per given in the question, we have
18 x 12 ÷ 4 + 5 - 6 ,
Apply the BODMAS Rule,
? 18 x 12/4 + 5 - 6
? 18 x 3 + 5 - 6
? 54 + 5 - 6
? 59 - 6 = 53

Solve All option one by one.
After changing the Sign.
25 + 15 ÷ 5 x 4 - 16 = 21
Apply the BODMAS Rule,
? 25 + 3 x 4 - 16 = 21
? 25 + 12 - 16 = 21
? 37 - 16 = 21
? 21 = 21

Solve all option one by one.
Change the symbol in given question.
From option (D),
4 A 3 M 2 L 4 D 2 M 6
4 + 3 X 2 < 4 ÷ 2 x 6
Apply the BODMAS Rule.
10 < 12

Interchange the symbol as per given in question.
6 ÷ 8 + 2 x 5 - 8
After changing the sign
= 6 x 8 ÷ 2 - 5 + 8
Apply the BODMAS Rule.
= 6 x 4 - 5 + 8
= 24 - 5 + 8 = 32 - 5 = 27