Which of the mathematical signs should be interchanged in the below equation to make it mathematically correct?
360 × 9 - 320 + 72 ÷ 5 = 80
- AOption (a)
- and ÷
- BOption (b)
- and ÷
- COption (c)
× and ÷
- DOption (d)
- and ×
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Correct answer
× and ÷
Why this answer is correct
Given equation: 360 × 9 - 320 + 72 ÷ 5 = 80.
BODMAS Table:

Let's check each option one by one.
Option 1) + and ÷
Given: 360 × 9 - 320 + 72 ÷ 5 = 80
After interchanging the signs we get;
⇒ 360 × 9 - 320 ÷ 72 + 5 = 80
⇒ 360 × 9 - 4.44 + 5 = 80
⇒ 3240 - 4.44 + 5 = 80
⇒ 3245 - 4.44 = 80
⇒ 3240.56 ≠ 80
⇒ LHS ≠ RHS
Option 2) - and ÷
Given: 360 × 9 - 320 + 72 ÷ 5 = 80
After interchanging the signs we get;
⇒ 360 × 9 ÷ 320 + 72 - 5 = 80
⇒ 360 × 0.03 + 72 - 5 = 80
⇒ 10.8 + 72 - 5 = 80
⇒ 82.8 - 5 = 80
⇒ 77.8 ≠ 80
⇒ LHS ≠ RHS
Option 3) × and ÷
Given: 360 × 9 - 320 + 72 ÷ 5 = 80
After interchanging the signs we get;
⇒ 360 ÷ 9 - 320 + 72 × 5 = 80
⇒ 40 - 320 + 72 × 5 = 80
⇒ 40 - 320 + 360 = 80
⇒ 400 - 320 = 80
⇒ 80 = 80
⇒ LHS = RHS
Option 4) + and ×
Given: 360 × 9 - 320 + 72 ÷ 5 = 80
After interchanging the signs we get;
⇒ 360 + 9 - 320 × 72 ÷ 5 = 80
⇒ 360 + 9 - 320 × 14.4 = 80
⇒ 360 + 9 - 4608 = 80
⇒ 369 - 4608 = 80
⇒ - 4239 ≠ 80
⇒ LHS ≠ RHS
Hence, the correct answer is "Option 3".















































