How to write the product matching range in the invention patent is more reasonable? For example, A: 80% ~ 90%, B: 1% ~ 6%, C: 0 ~ 9%, can we expand the scope?

It is ok to write like this, which is no problem for most people, but there is a danger. If someone proves that the excess part can't achieve the desired result of your patented technology scheme, you can directly declare your patent invalid, even if it is not a point. For example, 80%-90% is ok, and less than or greater than this range can not achieve the technical effect that the technical scheme wants to achieve. If you write 79%-90%, your patent only needs 79% to expire. This is nothing at ordinary times, but it may be encountered when it comes to rights disputes or lawsuits.