Sub Within 20 Strategies

Print: Ages 6–7 · 1–2 min · Foundation · Part Whole Counting · Independent Practice · Number Entry

Watch: Watch for 29, 11, or 18. Those entries show whether the learner added the visible numbers, copied the known star part, or copied the whole instead of finding the missing circle part.

Misread: The learner may answer how many stars or stickers there are, or may add 11 and 18. The answer requested is the remaining circle-sticker part that makes 11 + □ = 18 true.

Curriculum: This task uses a whole split into two disjoint parts and the relationship between addition and subtraction within 20. The scored skill is entering the one missing whole-number addend that makes the equation true.