Exploring number systems of other cultures can be an enjoyable learning experience that enriches students' knowledge of numbers and number systems in important ways. It helps students deepen mental computation fluency, knowledge of place value, and equivalent representations for numbers. This article describes how the author designed her explorations to focus on different cultures and different types of number systems. For seven months, she engaged her fourth- and fifth-grade classes in exploring number systems of different cultures once a week in one-hour segments. (Contains 6 figures.)