Counting Back and Counting On
http://illuminations.nctm.org/LessonDetail.aspx?ID=L103
A lesson plan for Grades K–2 Mathematics
This lesson, one of a seven-part unit from Illuminations titled “Links Away,” focuses on the counting model for subtraction. Students model numbers as a counting book is read. They then make a chain of links and write in vertical and horizontal format the differences suggested by adding and subtracting one link at a time from their chains. Finally, they draw a chain showing one link being taken away and write in two formats the difference it represents.
North Carolina Curriculum Alignment
Mathematics (2004)
Grade 1
- Goal 1: Number and Operations - The learner will read, write, and model whole numbers through 99 and compute with whole numbers.
- Objective 1.01: Develop number sense for whole numbers through 99.
- Connect the model, number word, and number using a variety of representations.
- Use efficient strategies to count the number of objects in a set.
- Read and write numbers.
- Compare and order sets and numbers.
- Build understanding of place value (ones, tens).
- Estimate quantities fewer than or equal to 100.
- Recognize equivalence in sets and numbers 1-99.
- Objective 1.03: Develop fluency with single-digit addition and corresponding differences using strategies such as modeling, composing and decomposing quantities, using doubles, and making tens.
- Objective 1.01: Develop number sense for whole numbers through 99.
- Goal 4: Data Analysis and Probability - The learner will understand and use data and simple probability concepts.
- Objective 4.01: Collect, organize, describe and display data using line plots and tallies.
Grade 2
- Goal 1: Number and Operations - The learner will read, write, model, and compute with whole numbers through 999.
- Objective 1.01: Develop number sense for whole numbers through 999.
- Connect model, number word, and number using a variety of representations.
- Read and write numbers.
- Compare and order.
- Rename.
- Estimate.
- Use a variety of models to build understanding of place value (ones, tens, hundreds).
- Objective 1.03: Create, model, and solve problems that involve addition, subtraction, equal grouping, and division into halves, thirds, and fourths (record in fraction form).
- Objective 1.04: Develop fluency with multi-digit addition and subtraction through 999 using multiple strategies.
- Strategies for adding and subtracting numbers.
- Estimation of sums and differences in appropriate situations.
- Relationships between operations.
- Objective 1.01: Develop number sense for whole numbers through 999.
- Goal 4: Data Analysis and Probability - The learner will understand and use data and simple probability concepts.
- Objective 4.01: Collect, organize, describe and display data using Venn diagrams (three sets) and pictographs where symbols represent multiple units (2's, 5's, 10's).
Kindergarten
- Goal 1: Number and Operations - The learner will recognize, model, and write whole numbers through 30.
- Objective 1.01: Develop number sense for whole numbers through 30.
- Connect model, number word (orally), and number, using a variety of representations.
- Count objects in a set.
- Read and write numerals.
- Compare and order sets and numbers.
- Use ordinals (1st-10th).
- Estimate quantities fewer than or equal to 10.
- Recognize equivalence in sets and numbers 1-10.
- Objective 1.03: Solve problems and share solutions to problems in small groups.
- Objective 1.01: Develop number sense for whole numbers through 30.
- Goal 4: Data Analysis and Probability - The learner will collect, organize and display data.
- Objective 4.01: Collect and organize data as a group activity.
- Objective 4.02: Display and describe data with concrete and pictorial graphs as a group activity.



