Montana Math MT.1.G.3

Math1st GradeGeometry

The Standard

Compose new shapes using two- and three-dimensional shapes.

2026 Montana Mathematics Content Standards

Teacher's field guide

What Students Need to Do: Students put flat shapes together to make a new flat shape. They also combine solid shapes, such as cubes and cylinders, to build a new object.
What Mastery Looks Like: A student can turn two matching right triangles to make a square and point to both triangles. They can build with blocks and name the solid shapes they used.
Common Misconceptions: Students may think turning a triangle changes what shape it is. They may name only the finished shape and miss the smaller shapes used to make it.
How to Assess It: Give each student two matching paper right triangles and ask them to make a square. Have them point to the two triangles in their square.

Lesson moves

Give students paper squares and triangles to arrange into a house, then have them trace and name each piece.
Show a square made from two triangles and ask, "What pieces do you see, and how did they fit together?"
Play build-and-copy: one student makes a model with cubes and cylinders, and a partner copies it and names the parts.
Show a photo of a toy castle, then ask students to build one with cubes and cylinders and point out those shapes.

Free download

$Preview of the MT.1.G.3 printable worksheet$

A ready-to-print activity worksheet aligned to MT.1.G.3, with an answer key for the teacher on its own page. No account needed.

PDF, US Letter, prints cleanly in black and white.

Keep exploring

Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.