You can have variables that are replaced dinamically while the progress bars animate. Might be overwhelming to understand them all but you can search the examples for easily understanding. A cheatsheet can be found below

{{perc}} - outputs the current percentage, for exaample if the progress is at 47% it will output 47%
{{perc-decimal}} - outputs the current percentage in decimal form, for example if the progress is at 47% it will output 0.47
{{perc100-decimal}} - it's the same as perc-decimal but the difference is it will go up until 1 even if the Percent is set to lower then 100%
{{center}} - it will center the element, currently available only for the Top propery
{{percmaxnr}} - outputs the current number relative the percent, you set the number in the Animation Number field. For example if progress is at 47% and the Animation Number is 500 - the output will be 235