Douglas Harmon 
Math Bath [EPUB ebook] 

Four rubber duckies floating in the tub, singing
rub a dub dub, one float away, theres only
three rubber duckies floating in the tub, singing
rub a dub dub, another float away, you only
have two rubber duckies floating in the tub,
singing rub a dub dub, two rubber duckies
floating in the tub, singing rub a dub dub, one
float away, you only have one rubber ducky,
sitting in the tub, hell be lonely but he will still
sing rub a dub dub.