Lab Manager Teacher Guide
Place Value Lab Manager
Lesson Guide: Subtraction Without Regrouping (4-Digit)
Grade Level
3rd Grade
Lesson Objective
Connect concrete place value disks to the vertical subtraction algorithm. Students will perform 4-digit subtraction without regrouping by modeling with disks and recording steps symbolically.
Materials Needed
- Place Value Lab Slides
- Disk Lab Manipulatives (Printed/Cut)
- Subtracting Steps Worksheet
- Place Value Mats (or large paper)
Instructional Flow
5 min
Warm-up: Disk Construction
Students use place value disks to build the number 4,567. Check for correct placement in Thousands, Hundreds, Tens, and Ones columns.
10 min
Video Instruction: Paused Modeling
Watch "Let's Learn - Subtraction Without Regrouping". Pause at each step of Example 1 (0:26 - 1:08) to have students replicate the action with their physical disks.
Prompt: "Which number goes on top in the vertical version? Why?"
25 min
Activity: Concrete to Abstract
Students work in groups of 3 with assigned roles:
1. Builder: Manipulates disks on the mat.
2. Writer: Solves using vertical algorithm.
3. Checker: Verifies steps and final answer.
Rotate roles after every problem on the worksheet.
5 min
Closure: Reflection
Class Discussion: "How did seeing the disks being taken away help you understand what was happening to the written numbers?"
Pro-Tips for Success
- The "Zero" Discussion: When subtracting 1,000 - 1,000, discuss why we don't usually write a leading zero in the answer (e.g., 0213 becomes 213).
- Subtraction Language: Use the "Subtract [X] from [Y]" phrasing to ensure students recognize the minuend (the total you start with).
- Visual Alignment: Encourage the 'Writer' to use the grid squares on the worksheet to keep place values perfectly aligned.
Place Value Lab Slides
Place Value Lab
Subtraction Without Regrouping
Grade 3 Mathematics
Warm-up: Lab Setup
Use your place value disks to build the number:
4,567
Thousands
Hundreds
Tens
Ones
Let's Learn
Embedded media
Watch closely! When the video pauses, use your disks to copy the steps.
Concrete to Abstract
The Builder
Sets up the disks and takes them away.
The Writer
Solves the problem on the worksheet using numbers.
The Checker
Checks both the disks and the numbers for mistakes.
Rotate roles every problem!
Lab Reflection
"How did the disks help you understand the written numbers?"
Visual
Concrete
Abstract
Disk Lab Manipulatives
Disk Lab Manipulatives
Print, cut, and use to model 4-digit subtraction.
Pro Tip: Print on cardstock for durability. Each group of three needs one set. These colors match the instructional video for visual consistency.
Thousands (1,000)
1,000
1,000
1,000
1,000
1,000
1,000
Hundreds (100)
100
100
100
100
100
100
Tens (10)
10
10
10
10
10
10
Ones (1)
1
1
1
1
1
1
1,000
1,000
1,000
1,000
1,000
1,000
100
100
100
100
100
100
10
10
10
10
10
10
1
1
1
1
1
1
Place Value Lab Mat
Place Value Lab Mat
Place your disks in the correct columns to build your number.
Thousands
Hundreds
Tens
Ones
Laboratory Property • 3rd Grade Math Division
