singular verb or plural verb for working hours

Question

It makes sense to say, "My working hours are from 9 am to 6 pm."

But is it right to say, "My working hours is from 9 am to 6 pm."

My argument is that from 9 am to 6 pm can be treated as a singular subject, as is "butter and bread".

Answer 1

Since you say 'my working hours', you are referring to each hour in which you work. The fact that they happen to come one after another and form a single stretch of time doesn't necessarily matter grammatically.

You could, for example, say 'my working hours are 9-10 o'clock on Monday, 11-12 o'clock on Tuesday, 9-10 o'clock on Wednesday...' etc and saying 'my working hours' would still be correct because there are multiple hours there, despite they're coming only one at a time.

Were you to use 'is', you would have to say something like 'my shift is from 9-6pm', as the word 'shift' bundles all those working hours into a singular entity, whereas 'working hours' remains plural.

Answer 2

Since you use hours you need 'are' .. You may say: my working time is from 9 am to 6 pm.

Answer 3

My shift is from 9 to 6

But shift is a noun in that sentence.