If you have Math Kit Bundle 2 — or you’ve been thinking about adding it to your classroom — the Sandcastle Play Mats are such a fun and flexible way to explore early number concepts through hands-on play.
🏖️ Find the Sandcastle Play Mats here!
Today I wanted to share one simple warm-up idea that helps students begin developing understanding of tens and ones in a very visual and playful way.
What You Need
- Sandcastle Play Mats
- Base ten blocks or connecting cubes
- A 20-sided or 30-sided dice
- Optional: one 6-sided dice
The Main Activity
Students roll a large dice and build the number on their sandcastle mat.They distribute:
- tens blocks to one section
- ones blocks to another section
18 = 1 ten and 8 ones
24 = 2 tens and 4 ones
The different levels of the sandcastle help students physically organize the quantity into parts.
Why It Works
The vertical sandcastle layout offers a slightly different visual experience from traditional tens-and-ones columns.For some students, the different “tiers” can help build an early understanding that:
- tens are larger quantities
- ones are smaller uantities
- numbers can be split into parts
Later, formal place value columns can naturally build from this understanding.
Make It Harder: Add Another Number
Roll a 6-sided dice and build a second number on another sandcastle mat.Then combine both numbers together.
For example:
- First castle: 18
- Second castle: 6
- 1 ten
- 8 ones
- 6 ones
- 10 ones for 1 new ten
The total becomes:
- 2 tens
- 4 ones
- = 24
Try Subtraction Too
Roll a 6-sided dice and subtract that amount from the original number.If needed, students can:
- remove a ten block
- exchange it for 10 ones
- then take away the amount needed
This helps students begin understanding that a ten can be split into smaller parts.
Partner Play Ideas
Students can also work with a partner:- build different numbers
- compare numbers
- decide which is larger or smaller
- discuss how many more or fewer