Build a Number with Tens and Ones
Explain a two-digit number as groups of ten and leftover ones.
Open lesson 1Think in Tens and Ones
Build, compare, and change two-digit numbers using groups of ten.
Before you begin
- Count objects to twenty, with an adult if helpful.
- Know that ten single marks can form one group.
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 Tens Before Ones
Use place value to decide which two-digit number is greater.
Open lesson 2Add One Whole Ten
Find ten more by changing the tens and keeping the ones.
Open lesson 3Take Away Whole Tens
Find a difference by removing groups of ten.
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.