Gum should definitely be allowed at school.
Firstly, you wouldn't need Blu Tack because gum is just as sticky.
Secondly, you won't talk because you will be too busy chewing.
Thirdly, it tastes good and you won't need any other food.
Lastly, if you have bad breath or you forget to brush your teeth, it will do the trick.
Therefore, I think it is definitely critical to have gum at school.
Persuasive Writing is when we give reasons to convince people of something we think is important and/or needs to be changed
e.g. people should not be allowed to have pets OR all children should be in bed by 6pm OR plastic bags should be banned