Help your students build strong number sense with this engaging set of addition and subtraction worksheets within 20. These activities use number lines, visual models, and word problems to support conceptual understanding and hands-on practice. Perfect for first grade math, this resource makes learning operations within 20 clear, interactive, and meaningful. What’s Included: Addition with number lines (0–10 and 0–20) Subtraction with number lines (0–10 and 0–20) Mixed addition & subtraction pr