First, if the child is slow, it may not be his procrastination, but his habitual slowness. Then you can urge him to tell him that the exam is time-limited, and it is not good to write too slowly, so he should exercise his quick logical thinking. You can stimulate children's quick thinking through some rewards, such as 1 hour to finish homework and watch cartoons for 30 minutes. After 40 minutes, you can watch cartoons for 50 minutes and do whatever you like to make him think quickly. But remember to grasp his seriousness and don't scribble just because you want to finish your homework quickly. For example, you can make a mistake and deduct 10 minute animation time.
Second, sometimes children themselves are unwilling to do it quickly, which is also a manifestation of playfulness. Although children's "default" homework is "hard work", some children will "unconsciously" seek pleasure in suffering, play while doing it, or want to play with their children during the day, which leads to procrastination. Such children need to concentrate on their work, and the method is relatively simple. You can pay more attention to the people or things that happened at school during the day when he is out of school every day, and ask him if he had fun with children today. In this way, on the one hand, you can learn more about your child, on the other hand, you can distract your child from his homework in advance, make him more focused on his homework, and then pay more attention to instilling the idea of doing things wholeheartedly. Such a child should try not to use the first method, because then he will miss cartoons when he is writing his homework and be easily distracted.
Third, this kind of child is relatively rare, but it can't be said that there is no such thing. It is because children are exposed to external things too early, which leads to confusion of children's logical thinking ability and too complicated or simple consideration of problems. I think many parents have sent their children to various cram schools long ago, and even some children who have been studying Olympic Mathematics for 1.2 years (I started studying in the fourth grade, that was more than 20 years ago), which inevitably leads to children thinking too much or too little about some less rigorous homework problems when doing homework, so it is difficult for parents to tutor such children. You have to teach them what kind of problems need to think too much. Just like when I first learned the principle of electromagnetic induction, I always thought too much about the force on the coil in the magnetic field.
In fact, in any case, I think the most important thing in educating children is to communicate with them more. If you can win the trust of your child 100%, then you are at least half successful.