Counting practice worksheets 1-20 | K5 Learning Worksheets; Math; Grade 1; Numbers & Counting; Counting 1-20 Buy Workbook. Download & Print Only $3.70. Counting practice (1-20) Counting by ones within 1-20 . In these counting worksheets, students fill in the missing numbers between 1 and 20. Open PDF. 1-20, with hints: Worksheet #1. 1-20, no hints: Worksheet #2. Within 1-20, with hints: Worksheet #3 Worksheet …