When you brush up on a math problem, there are only three words: x/2=x, and ask how many x is equal. The comment area was noisy, some people said that this question was wrong, how could 1 be equal to 2, and some people broke for a long time, only to find that the answer was hidden under their noses.

At first, I was confused, dividing both sides by x to get 1=2, isn't that? When I was right, I suddenly remembered what the middle school teacher often said: "When you encounter an unknown number as a divisor, first think about whether it can be 0." That's right, if x is 0, 0 = 2×0 is true, how can you divide the cost by x?

The pit of this problem is here, like a speed reduction belt on the road, which looks unremarkable and easy to get stuck if you don't pay attention.

When I think of doing application questions when I was a child, I always forgot about the writing unit, and I was circled out by the teacher and crossed out, and the reason is similar - it's not that I can't do it, it's that it's easy to ignore those "inconspicuous rules".

Some people joke that this question can measure mathematical sensitivity, but in fact, it is more like a test of care.

There are also often such things in life, such as forgetting to multiply the price when calculating electricity bills, and missing small numbers when buying things, which is obviously not difficult, but always makes mistakes in small places.

Have you figured out the answer? It's actually very simple, x=0. But the interesting part of this question is not in the answer, but in the easy pit to step on - like reminding us not to rush forward in our work, and occasionally stop to look at our feet, we may have to take a lot less road.