Georgia 1.NR.2.6
The Standard
Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers.
Georgia's K-12 Mathematics Standards · Explain the relationship between addition and subtraction and apply the properties of operations to solve real-life addition and subtraction problems within 20.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students find a missing number in an addition or subtraction equation within 20. The blank may appear at the beginning, middle, or end of the equation.
What Mastery Looks Like
- Students correctly solve equations such as 8 + ___ = 13, ___ - 4 = 7, and 15 - ___ = 9. They can check the missing number with counters, a drawing, or the related operation.
Common Misconceptions
- Students may treat the equal sign as a signal that the answer must come next. They may combine the visible numbers without considering the blank’s position, especially in subtraction equations.
How to Assess It
- Give students these exit-ticket equations: 7 + ___ = 15, ___ - 6 = 8, and 13 - ___ = 9. Ask them to solve one using a drawing.
Lesson moves
Ways to Teach It
Place 14 counters on a mat, hide some under a cup, and have students use the visible counters to find the hidden amount.
Ask students to explain why 6 belongs in both 8 + ___ = 14 and 14 - 8 = ___.
Play equation match by pairing cards such as 9 + ___ = 16, 16 - 9 = ___, and the number 7.
Present a snack problem: Mia had 15 crackers and ate some, leaving 9; students find how many she ate.
Free download
Printable 1.NR.2.6 Worksheet
A ready-to-print activity worksheet aligned to 1.NR.2.6, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
Download the worksheetKeep exploring
Related Standards
- 5.NR.3.4
Model and solve problems involving multiplication of a fraction and a whole number.
- 1.NR.5.1
Use a variety of strategies to solve applicable, mathematical addition and subtraction problems with one- and two-digit whole numbers.
- 2.NR.2.3
Solve problems involving the addition and subtraction of two-digit numbers using part-whole strategies.
- 3.PAR.3.7
Use multiplication and division to solve problems involving whole numbers to 100. Represent these problems using equations with a letter standing for the unknow...
Turn this exact standard into a lesson
Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.