Montana Math MT.2.OA.3
The Standard
Determine whether a group of objects, up to 20, has an odd or even number of members.
2026 Montana Mathematics Content Standards
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students count a collection of up to 20 objects. They make pairs to see whether every object has a partner or one is left over.
What Mastery Looks Like
- A student can pair 19 counters, find one left over, and call 19 odd. They can pair 18 counters with none left and call 18 even, even when the counters are scattered.
Common Misconceptions
- Students may call a group even because they can split it into two piles, even if the piles are different sizes. Scattered objects can also lead them to miss a pair or count one object twice.
How to Assess It
- Exit ticket: Show 14 dots and 15 dots. Ask students to circle pairs, label each total odd or even, and explain any leftover.
Lesson moves
Ways to Teach It
Give students 13 counters and have them make pairs, then name whether a counter is left without a partner.
Ask students to draw pairs of 16 and 17 buttons, then write what makes the two totals different.
Play Odd or Even Sort: students draw a number card from 1 to 20, build it with cubes, and sort the card.
Pose a field trip with 15 students and ask students to draw buddy pairs, then explain whether anyone is left out.
Free download
Printable MT.2.OA.3 Worksheet
A ready-to-print activity worksheet aligned to MT.2.OA.3, 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
Turn this exact standard into a lesson
Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.
Also for this standard:Make a WorksheetMake a QuizMake a Sub Lesson