Make a paper D20 die, decorate it, roll it many times, record results, and explore probability and averages with simple charts.


Step-by-step guide to make a paper D20 die
Step 1
Gather all your materials and set them on a clear table so you can work without losing anything.
Step 2
Find a D20 icosahedron net online and print it or draw a D20 net on your paper using a ruler and pencil.
Step 3
Cut out the D20 net carefully along the outer edges using scissors.
Step 4
Fold every triangle edge sharply along the crease lines so the net can form the 3D shape.
Step 5
Number each triangular face from 1 to 20 using your pencil, assigning each number once.
Step 6
Decorate each face with colors or small pictures so your die looks awesome and easy to read.
Step 7
Apply glue or tape to the tabs and assemble the net into a sealed 20-sided die.
Step 8
Give your finished die one gentle test roll to make sure it is sturdy and rolls freely.
Step 9
Open your notebook and draw a simple table with two columns labeled "Roll number" and "Result."
Step 10
Roll your D20 exactly 60 times and write each result in the table one row at a time.
Step 11
Tally how many times each number from 1 to 20 appeared using marks or counts in your notebook.
Step 12
Use your tally counts to draw a bar chart on a page showing the frequency for each number from 1 to 20.
Step 13
Add all 60 roll results together and divide by 60 to calculate the average (mean) roll.
Step 14
Write one short sentence about whether the results looked fair compared to the idea that each number should come up about equally.
Step 15
Share a photo of your decorated D20 and your chart on DIY.org so everyone can see your experiment.
Final steps
You're almost there! Complete all the steps, bring your creation to life, post it, and conquer the challenge!

Help!?
What can we use instead of printer paper, glue, or a pre-made D20 net if they aren't available?
If you can't print a D20 net or lack printer paper, draw the icosahedron net with a ruler and pencil on cardboard or an old cereal box and use strong clear tape instead of glue to assemble the tabs.
What should I do if the net won't fold into a clean 20-sided die or the tabs won't hold?
If the net won't form properly, re-cut any uneven outer edges, score and sharply fold every triangle edge with a ruler before applying glue or tape to the tabs, and let glued tabs dry under a light weight so the die seals and rolls freely.
How can I adapt the cutting, rolling, and recording steps for younger or older kids?
For preschoolers, use a pre-cut or pre-made D20 and record only 10 simple rolls with help, for elementary kids let them cut, number, decorate and complete the full 60-roll table and tally, and for teens add repeated trials, deeper stats like standard deviation, or redesign the net for sturdier materials.
How can we extend or personalize the experiment beyond rolling 60 times and making one bar chart?
You can personalize it by making several differently decorated D20s, sealing them with clear tape for durability, color-coding number ranges, comparing each die's bar chart and mean to the expected distribution, and sharing photos and results on DIY.org.
Watch videos on how to make and use a paper D20 die
Facts about probability and statistics for kids
🔺 A D20 is the shape of a regular icosahedron — it has 20 triangular faces and 12 vertices.
🎲 A standard D20 shows the numbers 1–20 and on a fair die each face has a 5% chance to come up.
🐉 D20s are famous in role-playing games like Dungeons & Dragons, where rolling a natural 20 often means a critical success.
📈 The average (expected) roll for a fair D20 is 10.5, right between 1 and 20.
🔁 The more times you roll and record results, the closer your experimental outcomes usually get to the true probabilities (Law of Large Numbers).


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