This year, my oldest will be in her third year of lower elementary, and I’ll be introducing decimal work (which she is super excited about!)
The Montessori Decimal Board (or decimal fraction exercise as it is sometimes called) consists of the board, decimal number cards, unit beads (green, blue, red), skittles (green, blue, red) and 60 cubes for each 6 colors that get lighter as the fraction become smaller.
Here you can find a short video showing the details from Allison’s Montessori
While this material is pretty affordable as Montessori materials go, I knew I could easily DIY it with many materials that I already had on hand!
Being a craft supply hoarder comes in handy sometimes!
When deciding if I should purchase or DIY a material, I always weigh it quite carefully. Time is a valuable thing for us mamas! It’s also important to keep in mind what you have on hand and what you’ll have to purchase, since sometimes the cost won’t be much less than buying. I’ll try and make it easy for you to decide by sharing links and prices below, but don’t be afraid to experiment with items you already have!
I’ve seen people make the decimal cubes/discs from felt or foam, or use a cricut to cut plastic!
Free Printable: Decimal Cards
Free Printable: Place Value Chart
As you can see, the water colors are where it can get a little pricey if you don’t have them on hand. The good news is, this project hardly used any of the paint at all, so you’ll be able to use it for projects the rest of the year. But, I’ve been told by other homeschool mamas that crayola washable paint, and water color pallets work great on unfinished wood as well.
- 6 ziplocks (sandwich size)
- White vinegar
- Paper towels
- Gloves (optional but encouraged)
Alright! On to the project!
Note: Scroll to the end if you prefer a brief summary of the process
So, this materials traditionally has 60 cubes for each decimal (tenths to millionths). Using the cubes linked above, I had enough for 33 cubes for each decimal color. If you’d like more, two packages would do it. I’m going to play it by ear here.
Dye the dark cubes first using the liquid water colors. I did this by pouring about 1/4 cup (maybe less) into a ziplock bag, and then dumping my pre counted cubes in. This step is important because the second you put those cubes in, they start sucking up dye. So you want them all in at once. Then, start shaking! Well… more like sloshing. Just keep them moving so that all sides are being covered. I definitely had to move faster than I anticipated! This process only took about 1-2 minutes tops. The reason I suggest dying the dark colors first, is because you want to make sure the lighter colors have enough contrast, and it’s easier to control the shade of the food dyed cubes than the water color. My green cubes ended up closer in shade than I would have liked, which was a bummer because I could have easily pulled the food dye cubes out sooner.
After the cubes soaked up enough dye, I simply poured the water color back into the bottle and laid the cubes out on a paper towel to dry. I put the paper towels on a cookie sheet to save my counters!
The lighter cubes! While the tenth, hundredth, and thousandth cubes are blue, red, and green. The ten-thousandth, hundred-thousandth, and millionth cubes are light blue, pink, and light green. (Side note, why does pink get its own name and we don’t call it light red????)
To attain these lighter shades I used 3TBSP of vinegar to 16-25 drops of food dye. The blue required the most drops and the longest sitting time (about 10 minutes being flipped and sloshed about every minute or so while I dyed the other cubes)
Surprisingly, I didn’t have to seal or coat the cubes in any way. We even tried to intentionally get the dye to come off onto our hands, without success.
After your cubes have dried, all that’s really left to do is sort them into your tackle box, add in the decimal cards, and get your board printed and laminated.
As for the beads, I intend to use the ones from our racks and tubes (long division) material, and the skittles from the stamp game. Just another beauty of homeschooling! You don’t have to have every material available at all times for a group of kids, which means you can pull from different boxes. If I didn’t already have these materials, I would purchase some pony beads (or other beads) and either use peg dolls for the skittles, or even push pins with the point clipped off.
As for presenting the lessons, I’ll be using this album here from Montessori Research and Development another great and free option can be found in the math albums here by Cultivating Dharma . I have both, because, honestly I just wanted to compare between MR&D and CD. You can also find some great instructions on how to present the material in this video
If DIY isn’t an option for you, and your budget can’t stretch to cover the actual material, I found a great printable version here at Making Montessori Ours I think this is a nice, quick solution if you’re in a pinch. But I do wonder if it would be a challenge to pick up the paper pieces?
Decimal Fraction DIY Summary
– Divide wood cubes into 6 even piles
– Starting with the liquid water color for the dark cubes, (blue, red, green) pour about 1/4 cup into a ziplock bag.
– Dump one pile of the cubes into the bag at once. Seal the bag, and slosh the cubes around until they’re the desired color.
– Pour water color back into the bottle and let cubes dry on a paper towel as you proceed with the other colors.
– For the light colors (lt. green, pink, & lt. blue), use the same process as above, but with food dye. Fill a ziplock bag with 3TBSP vinegar, and 16-25 drops of food dye. Occasionally compare colors with your dark cubes to ensure there is a contrast and they’re not getting too dark.
– Remove cubes, let dry, and sort into tackle box!