Lesson objective: Understand that ten ones are equal to one group of ten.

Students bring prior knowledge of ten ones from K.NBT.A.1: Compose and decompose numbers from 11 to 19 into ten ones and some further ones. This prior knowledge is extended to grouping 10 ones into a group of 10 as students create a box of 10 single cupcakes. A conceptual challenge students may encounter is accepting that 10 ones, or items, can be represented as one unit of ten.

The concept is developed through work with a tens frame, which shows 10 single items in one unit (the frame box).

This work helps students deepen their understanding of equivalence because 10 ones are equal to one group of ten, or one ten.

Students engage in Mathematical Practice 7, look for and make use of structure, as they repeatedly make units of ten using objects and draw circles in a tens frame. Students are asked to verbalize the concept of ten ones making one ten. Visualization of one unit of ten is developed as they see, and work with, various representations in the forms of a box of cupcakes, a tens frame, and other "grouped" objects.

**Key vocabulary:**

- bundle
- count
- group
- single
- ten
- ten frame

**Special materials needed:**

- crayons (blue, pink, green, yellow)
- cupcake cards - sheet included
- task instructions - sheet included
- tens frame recording sheet (for coloring cupcakes in task), an optional sheet is included.