This paper presents pilot testing of Owlet, a math program based on two original, tangible interface devices for primary school math and their accompanying apps. We built on prior work that demonstrated promising outcomes regarding manipulatives in math education and tangible user interfaces in a variety of applications. The Owlet program was pilot tested in ten classrooms, spanning students ages 5 to 11. We found that teachers used the exploratory activities to introduce the program, and other activities to encourage differentiated, student-paced practice of math concepts. Students were interested and engaged in using Owlet during the pilot tests, leading to student driven generation of challenges. Through development, Owlet, as a whole program, spanned more math concepts by prioritizing flexibility in one tangible interface and concreteness in the other. Our findings highlight the strengths and weaknesses of each tangible device.