Another group of participants completed a series of control exercises such as writing about their typical day to offer a comparison. (scienceofrelationships.com)
-- Prepare to train your brain by completing a series of challenging exercises with an emphasis on concentration skills and focus to train your working memory. (nintendo.co.uk)
I reckon it would be possible to win all 6 divisions of the new career in about 40 - 50 hours while completing every series in all the divisions would take over 120 hours. (xboxenthusiast.com)