Jay is enjoying the Life of Fred books (he's encountered so far very much) and the first 2 books tie in so well with M.M.M level 6.
L.O.F is a wonderful incentive to make sure other, less palatable, learning tasks are done.
See these samples if you'd like to see inside L.O.F books.
Daisy gets enthralled by what Fred is up to next and wants Jay to 'work' the math part out so they can move on with the story.
They valiantly plowed through the first book far quicker than I wanted Jay (them) to so I quietly put the second book "out of reach" for a while since I wanted us to use it for study now - using portions of our M.M.M text for further practice where, or as, needed.
L.O.F books are a hit in our home .... I like reading them too - wish math had been this much fun when I went to school :-)