A quick math problem on social media has caused controversy over whether it is correct or not. The problem was given with the sequence: '66 - 6 + 7 + 23 - 18 + 2'. The student followed the calculation rule from left to right and got the result of 74. However, the teacher gave a different answer and showed the correct way to calculate by combining the numbers that gave even results.

After the problem was posted, there were two opinions:

"You have the right to combine, but when you combine, the sign is wrong, so your result is still wrong," one account argued.

Meanwhile, a reader commented: "This is a quick calculation, requiring quick calculation so we have to combine the calculations that give the fastest result. Calculating like you is correct."