They were given demonstrations and answers to questions by 15 S3-S5 pupils.
They were shown various functions of the calculators, such as recurrence relations, straight line and graphs of function. A calculator linked to a Ranger motion detector plotted a pupil's movement across the room and a video showed the calculators' use in class.
Graphical calculators offer pupils a more investigative and time-saving approach that does away with the need for complex calculations. They also allow pupils to work more independently and check their answers.
A further appeal is their capacity to include games. A beat-the-clock format can help to develop mental numeracy.
The school's provision of graphical calculators has been limited to two class sets, but it hopes to get more in future and to encourage some pupils to buy their own.
Pauline Anderson, the principal teacher of maths, hopes to build the use of graphical calculators into S1 courses to explore topics such as decimals and fractions.
She says the evening was a great success. As with any new form of technology, parents were largely unfamiliar with its functions and were keen to learn.
Staff received free training from Texas Instruments, the manufacturer of the graphical calculators used at Kelso High, and a maths lecturer from Napier University underlined the calculators' importance in higher education maths courses.
Charlie Robertson, the rector of Kelso High, is delighted with the evening's success and says it was particularly helpful to have the technology explained by pupils.
The school has hosted similar events on Mind Mapping and other learning techniques.