The logic followed here is :-
By using BODMAS RULE :
Option 1) : ×, +, -, ÷, =
Given equation : 45 * 86 * 23 * 36 * 18 * 2021
After inserting the mathematical operators in given equation the equation is as follows : 45 × 86 + 23 - 36 ÷ 18 = 2021
⇒ 45 × 86 + 23 - 36 ÷ 18 = 2021
⇒ 45 × 86 + 23 - 2 = 2021
⇒ 3870 + 23 - 2 = 2021
⇒ 3893 - 2 = 2021
⇒ 3891 ≠ 2021
LHS ≠ RHS
Option 2) : +, -, ×, ÷, =
Given equation : 45 * 86 * 23 * 36 * 18 * 2021
After inserting the mathematical operators in given equation the equation is as follows : 45 + 86 - 23 × 36 ÷ 18 = 2021
⇒ 45 + 86 - 23 × 36 ÷ 18 = 2021
⇒ 45 + 86 - 23 × 2 = 2021
⇒ 45 + 86 - 46 = 2021
⇒ 131 - 46 = 2021
⇒ 85 ≠ 2021
LHS ≠ RHS
Option 3) : -, ×, +, ÷, =
Given equation : 45 * 86 * 23 * 36 * 18 * 2021
After inserting the mathematical operators in given equation the equation is as follows : 45 - 86 × 23 + 36 ÷ 18 = 2021
⇒ 45 - 86 × 23 + 36 ÷ 18 = 2021
⇒ 45 - 86 × 23 + 2 = 2021
⇒ 45 - 1978 + 2 = 2021
⇒ 47 - 1978 = 2021
⇒ 1931 ≠ 2021
LHS ≠ RHS
Option 4) : +, ×, -, ÷, =
Given equation : 45 * 86 * 23 * 36 * 18 * 2021
After inserting the mathematical operators in given equation the equation is as follows : 45 + 86 × 23 - 36 ÷ 18 = 2021
⇒ 45 + 86 × 23 - 36 ÷ 18 = 2021
⇒ 45 + 86 × 23 - 2 = 2021
⇒ 45 + 1978 - 2 = 2021
⇒ 2023 - 2 = 2021
⇒ 2021 = 2021
LHS = RHS
Hence, the correct answer is "+, ×, -, ÷, =".