Which of the mathematical signs should be interchanged in the below equation to make it mathematically correct?

3 + 78 ÷ 13 - 9 × 117 = 126

Given equation : 3 + 78 ÷ 13 - 9 × 117 = 126

Now, by interchanging the signs

• Option - (1) : + and -

3 + 78 ÷ 13 - 9 × 117 = 126 ⇒ 3 - 78 ÷ 13 + 9 × 117 = 126

3 - 6 + 9 × 117 = 126

3 + 1053 - 6 = 126

1056 - 6 = 126

1050 ≠ 126 (LHS ≠ RHS)

• Option - (2) : + and ×​

3 + 78 ÷ 13 - 9 × 117 = 126 ⇒ 3 × 78 ÷ 13 - 9 + 117 = 126

3 × 6 - 9 + 117 = 126

18 + 117 - 9 = 126

135 - 9 = 126

126 = 126 (LHS = RHS)

• Option - (3) : + and ÷ 

3 + 78 ÷ 13 - 9 × 117 = 126 ⇒ 3 ÷ 78 + 13 - 9 × 117 = 126

0.03 + 13 - 9 × 117 = 126

0.03 + 13 - 1053 = 126

13.03 - 1053 = 126

-1039.97 ≠ 126 (LHS ≠ RHS)

• Option - (4) : ÷ and ×

3 + 78 ÷ 13 - 9 × 117 = 126 ⇒ 3 + 78 × 13 - 9 ÷ 117 = 126

3 + 78 × 13 - 0.07 = 126

3 + 1014 - 0.07 = 126

1017 - 0.07 = 126

1016.93 ≠ 126 (LHS ≠ RHS)

Hence, "Option - (2)" is the correct answer.