Subtraction Within 20 — Practice Pack

Learning Objectives

• Subtract within 20 using take-away and counting-back strategies.
• Understand subtraction as "how many are left" and as "the difference between two numbers."
• Solve simple real-world subtraction word problems within 20.

How to Use This Resource

• Presentation (8 min): Model "counting back" on a number line: for 15 − 4, start at 15 and count back 4 (14, 13, 12, 11).
• Take-Away Model (7 min): Use counters to physically remove objects for 2-3 problems, connecting the action to the subtraction symbol.
• Guided Practice (10 min): Work through 3-4 problems together, encouraging students to choose counters, a number line, or mental subtraction.
• Independent Practice (10 min): Students complete the worksheet's subtraction grid and word problems.
• Wrap-up (5 min): Pairs check answers and explain their strategy for one problem.

Classroom Activity Ideas

• Show 12 counters, then take away 5 in front of the class while counting aloud. Ask: "How many are left?" Count together to check.

Differentiation

Struggling students: allow counters for every problem; keep numbers on the smaller end of the set (e.g. 10-13). Advanced students: ask them to also write the matching addition fact for two problems (e.g. 18 − 9 = 9, so 9 + 9 = 18).

Assessment

Review the completed subtraction grid; listen during wrap-up for correct strategy explanations.

Teacher Tips

If a student consistently subtracts the smaller number from the larger regardless of order (a common early error), go back to physical counters before returning to the abstract number line.

What's Included

• Complete Lesson Pack PDF (lesson plan + student worksheet + answer key)
• Standalone printable Answer Key PDF
• Thumbnail and preview images

Additional Files

• Answer Key (Printable) (PDF)

Teacher Reviews