Number naming, or knowledge of math numerals, has been described as a gatekeeper skill in preschool math development because it is necessary for later math tasks such as calculation. This article describes a small group intervention piloted with 10 preschoolers found to be at risk for delays in early numeracy development during universal screening. Target numerals were assigned randomly to one of three conditions (book, activity, and control). Using an adapted alternating treatment design, intervention conditions were delivered to small groups in 15-min sessions three times per week for 8 weeks. Each intervention session included a manualized counting book and activity, which were delivered in random order each session, but included the same numerals for number identification, verbal counting during one-to-one correspondence, and number naming. Across the 8 weeks of intervention, some preschoolers exhibited growth in number naming in intervention conditions as compared to control; participants varied in whether the book or activity intervention condition was more effective for their learning.