Texas Instruments Calculator

Here is the only guidance provided by the ACCA:

You are not permitted to use a dictionary or an electronic translator of any kind or have on or at your desk a calculator which can store or display text. You are also not permitted to use mobile phones, electronic communication devices or any item with smart technology functionality in the examination hall. These are known as “unauthorised items” and are taken into the examination hall at the candidates own risk. ACCA accepts no responsibility for their loss or damage. Such items must not be worn, or be placed on your desk, in pockets of clothing, in your bag or personal belongings, or be kept anywhere else on or about your person. If you bring a mobile phone, communication device or any item with smart technology functionality with you to your examination, you must declare this to the examination personnel upon entering the examination hall. You must switch the phone or electronic communication device off and disable any alarms or notifications. You must then follow the instructions given to you by the examination personnel.

So it depends on whether or not your calculator can store or display text. If it can not, then it is OK 🙂