Parents can positively impact children's learning of mathematics. To productively engage families in the learning process, teachers must support such interpersonal relationships. The author describes the investigative work of a group of teacher candidates as they sought to attain such understanding. Eighteen preservice teachers, who were enrolled in a university career-change master's degree program, interacted with thirty fourth-grade families as part of the required fieldwork of their mathematics methods course. These families participated in a parental engagement program titled "In Collaboration." Each preservice teacher worked with one or two families at four monthly two-hour family sessions. The goal of each family session was to spark communication among parents and children as they collaborated on fourth-grade curriculum-based tasks involving the use of classroom manipulatives to represent mathematical concepts. In addition to providing opportunities for parents to learn about classroom mathematical learning, these sessions also furnished a venue for the preservice teachers to investigate families' collaborative efforts while engaging in mathematical tasks. The preservice teachers used multiple forms of inquiry--including a survey, interviews, and observational field notes--to investigate their assigned families' collaborative efforts. A parent survey was administered at the beginning of the first family session. It consisted of twenty-seven statements requiring five-point Likert scale responses, and it revealed baseline parental perspectives on (a) ways parents should assist with their child's learning of mathematics and (b) ways teachers should support parents with their child's learning of mathematics. The parent interview was conducted at the beginning of the first family session, to inquire about (a) how parents primarily assist their child in mathematics, and why; (b) the challenges and related reasons, if any, parents face while assisting their child in mathematics; and (c) how parents desire teachers to support them with their child's learning of mathematics. The benefits of interacting with families were clear for the preservice teachers.