Subtraction: Foundations by Richard Garcia Subtraction: Foundations Course Content Lessons Status 1 Doing Subtraction By Crossing Out Lines 2 Doing subtraction By Making A Group 3 Doing Subtraction By Making Two Groups 4 Practing Subtraction by Doing The Same Problem 5 Lesson 6 Subtracting From Numbers Larger Than 10 7 A Shortcut To Subtracting Numbers Larger Than 10 8 Subtracting By Borrowing From 10 9 Deciding When To Borrow From 10 10 Learning To Borrow From Numbers Bigger Than 10