Each slide is dense with row after row of numbers, bullet points are strewn about generously on each page and complex graphs are squeezed in four to a slide.
But the singers all handled themselves well, although none were forced to sing more than one or two numbers in a row (so not a particular test of live ability).
Within the study, participants were asked to quickly scan a row of digits and cross out consecutive numbers that add to a pre-specified total (for example, any two numbers that total 3).