At first, i think it's just another time travel or parallel world TV drama like the Taiwanese drama "Someday or One day" but indeed the content is more than this which is an amalgam of mathematics, genius vs mediocrity, family and love.
The whole story can basically be divided into three parts. The first part is about traveling back to childhood world. It may not be too difficult to use the current intelligence to cope with the selection of the primary grade Mathematical Olympiad, but it's challenging to ensure that every one in the group photo can survive to the end. That's a very interesting storyline and every kid actor acts very well and natural. This story can be regarded as the most passionate part that i like the most! Though the pace in the second time travel is a bit slow, it keeps bringing you surprises and controversial issues like what Lin Zhaoxi believes it's rather a cheating than refurbishing when rerunning the life in the parallel world.
When it comes to last two episodes, it reminds the concept of Sliding door, whether or not Lin can pick up her new born girl, the story shows two parallel lives of Zhaoxi's family, but at the same time, it explains well all cause and effect relationship in two parallel worlds, every little step is so correlated.
The most heart breaking part is the last words left to Zhaoxi before her mum's dying, as a mother, I can just feel the sincere and touching maternal love. Overall, highly recommended!