Sınav sırasında hesap makinesi kullanmak yasak.

Sırasında means during or in the course of.

So sınav sırasında = during the exam.

This is a very common Turkish way to express during X:

• ders sırasında = during class
• toplantı sırasında = during the meeting
• yemek sırasında = during the meal

It is more specific than just saying in the exam; it emphasizes the time period when the exam is happening.

Yes. Hesap makinesi literally means something like calculation machine, and that is the normal Turkish word for calculator.

It is a noun compound:

• hesap = calculation/account
• makinesi = machine

Together, they form the standard expression for calculator.

Because hesap makinesi is an indefinite noun compound, which is very common in Turkish.

In this type of compound:

• the first noun stays plain: hesap
• the second noun takes a compound ending, usually -(s)ı / -(s)i / -(s)u / -(s)ü

So:

• hesap + makine becomes hesap makinesi

This -si does not mean his/her/its in this sentence. It is just part of the compound structure.

Other examples:

• kahve fincanı = coffee cup
• otobüs durağı = bus stop
• telefon numarası = phone number

Turkish does not use articles like a/an and the the way English does.

So hesap makinesi can mean different things depending on context. In this sentence, it is best understood as a generic meaning:

• using a calculator
• or in natural English, even using calculators

The sentence is talking about the activity in general, not one specific calculator.

Because kullanmak here is an infinitive: to use / using.

Turkish often uses the infinitive ending -mak / -mek to turn a verb into a noun-like idea. In this sentence:

• hesap makinesi kullanmak = to use a calculator / using a calculator

That whole phrase acts like the subject of the sentence.

So the structure is basically:

• [Using a calculator] [is forbidden].

Other similar examples:

• Sigara içmek yasak. = Smoking is forbidden.
• Burada park etmek yasak. = Parking here is forbidden.

Because the object is non-specific.

In Turkish, a direct object usually stays without the accusative ending if it is general or indefinite:

• hesap makinesi kullanmak = to use a calculator / to use calculators in general

If you were talking about one specific calculator, you would normally use the accusative:

• hesap makinesini kullanmak = to use the / that specific calculator

So in this sentence, the plain form fits because the rule is general, not about one particular calculator.

Because Turkish often leaves out the present-tense to be in third-person statements like this.

So:

• yasak = forbidden
• kullanmak yasak = using it is forbidden

This is completely normal Turkish. English needs is, but Turkish usually does not here.

You can think of it as:

• Sınav sırasında hesap makinesi kullanmak (dır) yasak.

But in everyday Turkish, that extra copula is usually not spoken.

Yes. Yasaktır is correct and sounds more formal, official, or written.

Compare:

• Sınav sırasında hesap makinesi kullanmak yasak. = natural, simple
• Sınav sırasında hesap makinesi kullanmak yasaktır. = more formal, like a rule or notice

The ending -tır / -tir / -tur / -tür adds a formal or emphatic tone.

You will often see yasaktır on signs, rules, and official announcements.

Yes, Turkish word order is flexible, but this order is very natural.

Here the sentence is:

• Sınav sırasında = during the exam
• hesap makinesi kullanmak = using a calculator
• yasak = forbidden

Turkish often puts time expressions near the beginning and keeps the main predicate at the end.

This sentence sounds very natural because it first sets the context (during the exam) and then gives the rule.

Other orders are possible, for example:

• Hesap makinesi kullanmak sınav sırasında yasak.

That is understandable, but the original version sounds smoother and more typical.

Yes, and it is also common. But there is a slight difference in feel.

• Sınav sırasında = during the exam
• sınavda = in the exam / on the exam / during the exam, depending on context

So:

• Sınav sırasında hesap makinesi kullanmak yasak. clearly focuses on the time period of the exam
• Sınavda hesap makinesi kullanmak yasak. is also natural, but sınavda can sometimes feel a little broader or slightly more context-dependent

If you want to be very clear about during the exam session, sırasında is excellent.

Yes. A very formal version would be:

Sınav sırasında hesap makinesi kullanılması yasaktır.

This literally means something like The use of a calculator during the exam is forbidden.

What changed?

• kullanmak = to use / using
• kullanılması = its being used / the use of it

This kind of structure is especially common in regulations, notices, and official writing.

So:

• ... kullanmak yasak = simple, direct, everyday rule style
• ... kullanılması yasaktır = more formal, bureaucratic, official style