In "The number of hours that we are allowed to work has decreased." To what does the clause "that...work" relate?
In "The number of hours allowed is taken into consideration." To what does "allowed" relate?
In " The number of people killed has increased." To what does "killed" relate?
Same question for "that have been killed" in "The number of people that have been killed has increased."
If I say " The number of hours that are allowed is taken into consideration." To what does the clause "that are allowed" relate? Is it about adjectival clause to "number of hours"?
CF "sold" in "The list of goods sold should be given." To what does "sold" relate?
... there is no Adjectival Clause to "number of hours"
Your fundamental misunderstanding of that clause suggests that you might have simply misread the other clauses, and that the extracts in respect of which you are seeking advice have possibly been taken out of context.
In "The number of hours that we are allowed to work has decreased." To what does the clause "that...work" relate? answer-the number of hours
In "The number of hours allowed is taken into consideration." To what does "allowed" relate? answer-the number of hours
In " The number of people killed has increased." To what does "killed" relate? answer-the number of people
Same question for "that have been killed" in "The number of people that have been killed has increased." answer-the number of people
If I say " The number of hours that are allowed is taken into consideration." To what does the clause "that are allowed" relate? Is it about adjectival clause to "number of hours"?answer-the number of hours
CF ( by cf do you mean compare"sold" in "The list of goods sold should be given." To what does "sold" relate?<b.answer- the goods
Sorry, in my previous answers it may be that you can drop the 'number of' bit. Unfortunately I'm not sure of what the questions are getting at. What is the context- what's the course?