Even teacher offerred to sit with him and teach him one by one, he still did not want to do it either or he can only handle it for 15 minutes and wanted to quit. Later on, they told me that they downgraded the
worksheet level to let him do kindergarten works as review and he was able to handle it so fast, After gaining confidence, then they gradually started to throw in some first grade works in between and he is able to accept and do it.