Public learning track
Addition and Subtraction Fact Strategies Within 20
1st Grade · Math · Open Global Math
12 lessons
Goal
Master addition and subtraction facts within 10 and develop flexible mental strategies within 20.
Featured Diagrams
Adding Zero and the Identity Property Within 10
12 lessons
0 of 12 done
- 1Adding Zero and the Identity Property Within 10Up nextStart
- 2Subtracting Zero and Subtracting All Within 10PremiumNot started yet
- 3Counting On by 1, 2, and 3 to Add Within 10Not started yet
- 4Counting Back by 1, 2, and 3 to Subtract Within 10Not started yet
- 5Using Doubles Facts to Add Within 20Not started yet
- 6Using Doubles to Solve Near Doubles Within 10Not started yet
- 7Using Doubles Plus One and Doubles Minus One Within 20Not started yet
- 8Making Ten to Add Within 20Not started yet
- 9Breaking Apart to a Ten to Subtract Within 20Not started yet
- 10Using Addition Facts to Solve Subtraction Within 10Not started yet
- 11Using Think-Addition to Subtract Within 20Not started yet
- 12Selecting Efficient Mental Strategies Within 20Not started yet
Standards Covered
- OGM.2.OA.1Open Global Math Standards 2026™ · Math · Level 2 / Grade 1 (Age 6) · Grade 1Demonstrate computational fluency for addition and subtraction facts within 10, and mental flexibility within 20, utilizing robust strategies including counting on, counting back, making ten, decomposing to a ten, using doubles and near-doubles, and adding zero.
- OGM.2.OA.2Open Global Math Standards 2026™ · Math · Level 2 / Grade 1 (Age 6) · Grade 1Apply properties of operations (commutative property of addition, associative property of addition, and identity property of zero) as deliberate mental and written calculation strategies for adding two or three whole numbers whose sum is within 20 (and up to 100).
- OGM.2.OA.3Open Global Math Standards 2026™ · Math · Level 2 / Grade 1 (Age 6) · Grade 1Understand subtraction as an unknown-addend problem and recognize the inverse relationship between addition and subtraction, utilizing fact families, part-whole bar models, and balance scales to verify computations.
Curriculum Framework
1st Grade · Math · Open Global Math
1
12 lessons
Addition and Subtraction Fact Strategies Within 20
Master addition and subtraction facts within 10 and develop flexible mental strategies within 20.
2
8 lessons
Properties of Addition and Mental Strategies
Apply the commutative, associative, and identity properties to calculate sums within 20 and up to 100.
3
8 lessons
Fact Families and Part-Whole Relationships
Connect addition and subtraction through fact families, bar models, and balance scales.
4
8 lessons
Understanding Equivalence and Equations
Understand the equal sign as balance, evaluate true/false equations, and solve missing-number equations in all positions.
5
9 lessons
Word Problems: Addition and Subtraction Within 100
Solve one-step and two-step addition and subtraction word problems across various situation types within 20 and extending to 100.
6
9 lessons
Equal Groups, Arrays, and Early Multiplication
Build multiplication and division concepts through equal groups, repeated addition, equal sharing, and rectangular arrays.
7
8 lessons
Repeating, Growing, and Cyclical Patterns
Identify, describe, extend, and create repeating, growing, and cyclical patterns using shapes, objects, sounds, and numbers.