Virginia SOL 2.NS.1.i
The Standard
Represent odd numbers (up to 50) with concrete objects, using two equal groups with one leftover or two equal addends plus 1.
Virginia Standards of Learning for Mathematics · The student will utilize flexible counting strategies to determine and describe quantities up to 200.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students split a collection of up to 50 objects into two matching groups and identify the single object that remains. They connect the model to an equation with equal addends and 1 more.
What Mastery Looks Like
- A student can model any given odd number through 49 with two matching groups and one extra object. They can write a matching equation, such as 23 = 11 + 11 + 1.
Common Misconceptions
- Students may call a number odd whenever objects are left over, even if they did not make two equal groups. Some write unequal addends, such as 11 = 6 + 4 + 1, or forget the extra 1.
How to Assess It
- Give students 19 counters and ask them to prove 19 is odd with two equal groups, then write a matching equation.
Lesson moves
Ways to Teach It
Give pairs 27 counters and two plates, then have them split the counters equally and place the leftover counter between the plates.
Ask, “How does 17 = 8 + 8 + 1 prove 17 is odd?” Students answer with a drawing and one sentence.
Play Odd Build: draw a number card, build two equal cube towers plus one cube, and earn a point for an accurate equation.
Have students arrange 25 classroom chairs into two equal rows, then explain why one chair cannot join either row.
Free download
Printable 2.NS.1.i Worksheet
A ready-to-print activity worksheet aligned to 2.NS.1.i, 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
- K.NS.1.j
Group a collection of up to 100 objects (e.g., counters, pennies, cubes) into sets of ten and count by tens to determine the total (e.g., there are 3 groups of ...
- 2.NS.1.j
Determine whether a number (up to 50) is even or odd using concrete objects and justify reasoning (e.g., dividing collections of objects into two equal groups, ...
- 1.NS.1.e
Group a collection of up to 120 objects into tens and ones, and count to determine the total (e.g., 5 groups of ten and 6 ones is equal to 56 total objects).
- 2.NS.1.h
Represent even numbers (up to 50) with concrete objects, using two equal groups or two equal addends.
Turn this exact standard into a lesson
Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.