《MathStart》系列為美國HarperCollins出版的暢銷數學啟蒙書。作者Stuart J. Murphy認為數學與日常生活息息相關，他為了建立小朋友基礎的數學概念與知識，讓小朋友輕鬆愉快地學習數學，因而精心設計了這套生活化的《MathStart》數學啟蒙繪本，從生活話題與情境故事，讓小朋友有效地吸收數學概念。
全系列分為三個Level，Level 1著重於基礎認知上。
《Double the Ducks》是講述一個男孩子要照顧五隻小鴨子，然後這五隻小鴨子又各帶一個朋友回來。現在有十隻鴨子，雙倍的工作量。一個小男孩要如何完成這一項任務呢？透過有趣的故事，讓小朋友掌握雙倍的概念。
書內還會介紹不同的遊戲讓小朋友強化《雙倍》的概念。
同系列書藉：
Math Start Level 1 Monster Musical Chair
The young cowboy has his two hands full with five little ducks. They need three sacks of food and four bundles of hay. And when they each bring home a friend, it's twice as much work. For 10 little ducks, he needs double the food, double the hay and double the hands!
The first step in mastering basic addition is adding a number to itself (for example, 3+3).
Books in the same series:
Math Start Level 1 Monster Musical Chair
Paperback / For Ages: 3-7 / 40 pages