Building on previous findings that preschool children develop an awareness of base-ten structure from informal exposure to multidigit numbers, we tested whether kindergarten children would benefit from formal place value instruction, using this informal foundation as a starting point. A total of 124 U.S. kindergarten students participated in a school-based study that used a pretest-training-posttest design. One group of students completed 20 brief lessons focused on the relational structure of base-ten symbols, using activities informed by cognitive science research on relational learning. A second group of students completed 20 practice sessions on single-digit addition and subtraction problems. Both groups showed growth in place value understanding, but students in the experimental curriculum showed greater growth than children in the control group on measures that required precise understanding of base-ten syntax (i.e., counts of base-ten units). (PsycInfo Database Record (c) 2024 APA, all rights reserved) (Source: journal abstract)