Views
Plays
Making 20 Worksheet | Grade 1 Essential Math
Paste this activity's link or code into your existing LMS (Google Classroom, Canvas, Teams, Schoology, Moodle, etc.).
Students can open and work on the activity right away, with no student login required.
You'll still be able to track student progress and results from your teacher account.
This Grade 1 math worksheet focuses on the fundamental skill of finding missing addends to reach a sum of 20. By engaging with 18 structured multiple-choice problems, students develop the numerical fluency required for more complex algebraic thinking. The clear layout ensures that learners can focus entirely on the mathematical relationships without distraction.
At a Glance
- Grade: 1 · Subject: Math
- Standard:
CCSS.MATH.1.OA.D.8— Determine the unknown whole number in an addition equation relating three numbers- Skill Focus: Missing Addends to 20
- Format: 2 pages · 18 problems · Answer key included · PDF
- Best For: Independent practice or quick formative assessment
- Time: 10–15 minutes
What's Inside: This resource contains two pages of focused practice. Each of the 18 questions presents an addition equation where one addend is missing, and the sum is consistently 20. Students must select the correct missing value from four multiple-choice options. This format helps reduce writing fatigue while maintaining high cognitive demand for mental math and fact recall.
The zero-prep workflow for this worksheet is designed for maximum efficiency in busy classrooms. First, print the two-page PDF (30 seconds). Second, distribute the sheets to students for a quiet independent work block (1 minute). Third, use the included answer key for rapid grading or peer-review sessions (under 2 minutes). This makes it an ideal choice for emergency sub plans or transition periods.
Standards Alignment: This worksheet is directly aligned with CCSS.MATH.CONTENT.1.OA.D.8, which requires students to determine the unknown whole number in an addition or subtraction equation relating three whole numbers. For example, it specifically addresses the "19 + ? = 20" structure. This standard code can be copied directly into lesson plans, IEP goals, or district curriculum mapping tools.
How to Use It: Use this worksheet as a fluency builder during your morning routine to sharpen mental math skills. Alternatively, assign it as an exit ticket after a lesson on "friends of 20" to gauge student mastery. Teachers should observe if students are counting on their fingers or using known facts to identify those who need additional intervention. Expected completion time is 12 minutes.
Who It's For: This resource is primarily designed for first-grade students mastering basic addition facts. It also serves as an excellent review for second graders or a scaffolded intervention for older students working on foundational numeracy. It pairs naturally with base-ten blocks or number lines to provide visual support for learners who are not yet fluent.
According to the RAND AIRS 2024 report on elementary mathematics, frequent exposure to structured missing-addend problems is a critical predictor of later success in algebraic reasoning. This worksheet provides the repetitive, low-stakes practice necessary to move students from concrete counting to abstract retrieval. By focusing on the sum of 20, the resource reinforces the base-ten system and prepares students for regrouping. The multiple-choice format aligns with evidence-based practices for reducing cognitive load during the initial stages of skill acquisition. Research indicates that students who master these foundational "make ten" and "make twenty" combinations demonstrate significantly higher confidence when approaching multi-digit addition. This resource ensures that the standard CCSS.MATH.1.OA.D.8 is met through rigorous, targeted application, providing teachers with reliable data on student progress toward grade-level mastery.
