Math Worksheet · Grades 1–2
Adding Within 20 Worksheet
Free printable addition-fluency worksheet for grades 1-2. Students practice 46 mixed-format items – horizontal facts, missing addends, vertical sums, fact-family triangles, and short word problems – with a reference box that previews the make-ten and doubles strategies. Includes a complete answer key.
Subject
Math
Grades
Grades 1–2
Skill Focus
Adding Within 20, addition and subtraction
Lesson Length
20 minutes
Lesson Overview
About this worksheet
Adding within 20 is a foundational fluency goal for grades 1 and 2. This worksheet practices the same fact families in horizontal, vertical, missing-addend, and word-problem formats so students build durable, format-independent fluency.
A reference box at the top of page 1 previews the make-ten strategy, the small doubles (4+4 and 5+5), and doubles-plus-one. The examples deliberately use facts different from the assessed items so the reference teaches the strategy without revealing answers.
Page 3 is a complete answer key that shows the operation line for every missing-addend and word-problem item, which makes it easy for students or aides to spot-check work.
How to Use This Lesson
Warm up by reading the reference box aloud and modeling one make-ten example.
Time Section A as a 3-minute fluency check if students are ready.
Use Sections B-D for guided practice, pair-share, or homework.
Use Section E (word problems) as a 5-minute exit ticket.
Use the answer key on page 3 for student self-check or aide spot-check.
Printable Resource
A classroom-ready PDF with everything in one printable resource.
Free Member Resource · Printable PDF · 3 pages · Answer Key
Adding Within 20 Worksheet
Free printable addition-fluency worksheet for grades 1-2. Students practice 46 mixed-format items – horizontal facts, missing addends, vertical sums, fact-family triangles, and short word problems – with a reference box that previews the make-ten and doubles strategies. Includes a complete answer key.
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