Difficult question for the runner-up of Road to Olympia and 3 climbers

This is the Math question of the final round of the show Road to Olympia that made 4 contestants give up.

In the final round of the Road to Olympia to find the champion with a scholarship worth 40,000 USD (about 900 million VND), an extremely brain-teasing Math question appeared. The question was as follows:

"A student writes 10 natural numbers from 1 to 10 on the board and then plays the following game: Each time the student erases two random numbers a and b and then writes them on the board (ab 1). After 9 consecutive games, what numbers are left on the board?"

Faced with this question, contestant Hai An tried to reason but could not find the answer. Immediately after, the question was asked to the remaining contestants but no one could find the answer.

The final round puzzle of the Road to Mount Olympia was difficult for all 4 climbers.

If you find the answer in the shortest time, scroll down to the comments to record and see how many people think the same as you.

Lam Hoang

Source: https://vtcnews.vn/cau-hoi-lam-kho-a-quan-duong-len-dinh-olympia-cung-3-nha-leo-nui-ar947296.html