Measure When an Object Does Not Start at Zero
Locate the stated start and end marks.
About 15 minutes, plus any extended practice
Open lesson 1Measure Standard Lengths and Number-Line Changes
Read ruler intervals, compare unit sizes, find differences, and model changes on a line.
Before you begin
- Measure using equal units; subtract within one hundred.
Choose by skill rather than age alone. Read with an adult when useful, revisit a lesson, or explore another grade.
Follow the lesson sequence
Compare Measurement Counts Using a Known Unit Relation
Use the supplied exact relation between long and short units.
About 15 minutes, plus any extended practice
Open lesson 2Find How Much Longer in the Same Unit
Write both supplied lengths with matching unit labels.
About 15 minutes, plus any extended practice
Open lesson 3Model Addition and Subtraction as Number-Line Jumps
Mark the supplied start, move in the stated direction by the stated amount, and record the end.
About 15 minutes, plus any extended practice
Open lesson 4Review and transfer
After the lessons, try 4 new review cases and a practical task. Each answer has an explanation and a link back to the related lesson.
Open the unit reviewGuest answers are temporary. Keep your own paper or document; this unit does not certify completion or record a school grade.
Topic references
- Common Core State Standards, mathematics: 2.MD.A.1 — Read ruler intervals, compare unit sizes, find differences, and model changes on a line.
- Common Core State Standards, mathematics: 2.MD.A.2 — Read ruler intervals, compare unit sizes, find differences, and model changes on a line.
- Common Core State Standards, mathematics: 2.MD.A.4 — Read ruler intervals, compare unit sizes, find differences, and model changes on a line.
- Common Core State Standards, mathematics: 2.MD.B.6 — Read ruler intervals, compare unit sizes, find differences, and model changes on a line.
These references informed the topic selection. They do not certify complete standards alignment.