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NumberVerse — a number-building workshop: kids composing with base-ten blocks and a rekenrek bead frame under a tick-mark number line, no numerals

NumberVerse

Numbers are built — place by place, jump by jump. Compose them from base-ten blocks and the number line, then meet the guides who each teach one piece of number sense.

Build a number On the number line
Level 1

Start here

Number Studio Build a number from thousands to ones — watch standard, expanded & word forms update, and regroup 10-for-1. Number Line Place a number, round, work with integers & absolute value — solve by choosing your own jumps. Integer Order Which is larger — -3 or -5? Predict, then watch both land on the line. Rekenrek A quick-look bead rack — see a quantity in fives and tens, and build make-ten pairs.
Brain Break Take a quiet moment between rounds — a fun teaser or a short breather. Brain breaks help you remember what you learn.

All activities

Build & reason

Number Studio Compose a number from base-ten blocks; standard/expanded/word forms update as you trade 10-for-1. Number Line Place, round to the nearest ten or hundred, and work with integers and absolute value. Integer Order Predict which negative is larger, then watch both land — beats the “bigger digit” trap. Rekenrek See quantities in fives and tens without counting; build make-ten pairs.

Practice & play

Practice the concepts 12 kits from place value up to integers & absolute value, with a hint whenever you get stuck. Number Duel Head-to-head kit round for 2–4 players — one device or an online room by code. No chat, no accounts. Mixed Practice Shuffles the kits you’ve learned and brings them back when they’re ready to review. Teach the Cast Teach a number-sense idea to a cast member still learning it — teaching makes it stick.
Concept Kits — 12 kits of number sense

From place value up to integers and absolute value — a short round with a hint whenever you get stuck. Progress stays on this device.

Kit 1: Place Value: Whole Numbers Place value · grades 4-5 · 25 questions Kit 2: Place Value: Decimals Place value · grades 6-7 · 25 questions Kit 3: Multi-Digit Addition & Subtraction Operations · grades 4-5 · 25 questions Kit 4: Multi-Digit Multiplication Operations · grades 4-5 · 25 questions Kit 5: Division with Remainders Operations · grades 4-5 · 25 questions Kit 6: Estimation Strategies Estimation · grades 6-7 · 25 questions Kit 7: Properties of Operations Operations · grades 6-7 · 25 questions Kit 8: Factors & Multiples Factors & primes · grades 4-5 · 25 questions Kit 9: Prime & Composite Numbers Factors & primes · grades 4-5 · 25 questions Kit 10: Integers on a Number Line Integers · grades 6-7 · 25 questions Kit 11: Integer Operations Integers · grades 8-9 · 25 questions Kit 12: Absolute Value & Order Integers · grades 6-7 · 25 questions

For grown-ups — progress report →A private, on-device snapshot mapped to the skill areas practiced. Export a CSV or print — nothing that names you leaves this device.

Cast, stories & more

More ways to play

Quiz Arena Math Run Bean Machine Commit Number Twelve point three overs Difficulty plus execution
Where this idea comes from

Fibonacci’s Liber Abaci

Leonardo of Pisa, later called Fibonacci, learned Hindu-Arabic numerals as a boy in North Africa. In 1202 he wrote Liber Abaci, the Book of Calculation, to teach them in Europe.

One thing to hold: A handwritten book that opens with the nine figures and the zero, and how a digit’s place changes its value.

Why it matters: With place value, the same ten symbols can write any number, and adding and multiplying become methods on paper. The book’s puzzle about breeding rabbits gave us the Fibonacci numbers.

What we don’t know: No copy from 1202 survives; we read the revised version he made in 1228.

Sources: L. E. Sigler, Fibonacci’s Liber Abaci: A Translation into Modern English (Springer, 2002) · Keith Devlin, The Man of Numbers (2011)

The Ishango bone

A baboon leg bone with groups of notches, found in 1950 by the geologist Jean de Heinzelin at Ishango, by Lake Edward in what is now the Democratic Republic of the Congo. It is about 20,000 years old and is kept in Brussels.

One thing to hold: A dark brown bone about ten centimetres long, with a piece of quartz fixed at one end and three columns of cut marks.

Why it matters: It is one of the oldest objects that may show people keeping count with marks — the same idea as a tally.

What we don’t know: Nobody knows what the marks meant. Some have said they show prime numbers or a calendar; many researchers think that reads too much into a few notches.

Sources: Royal Belgian Institute of Natural Sciences, Brussels (the Ishango bone) · Jean de Heinzelin, “Ishango”, Scientific American 206 (June 1962)

Khipu

Knotted cords used in the Andes to record numbers and other information; the Inka state used them across its empire, and khipu are still kept by some Andean communities today.

One thing to hold: A main cord with hanging cords; knots placed in rows by tens, hundreds and thousands.

Why it matters: A place-value system made of knots: where a knot sits on the cord says what it is worth.

What we don’t know: Many khipu may record more than numbers, and how to read those is still being worked out.

Sources: Gary Urton, Inka History in Knots: Reading Khipus as Primary Sources (University of Texas Press, 2017) · L. Leland Locke, The Ancient Quipu or Peruvian Knot Record (1923) · The Harvard Khipu Database Project

NumberVerse mascot

Meet the cast — the characters who teach this

Each one stands for an idea you’ll practice. Tap a character to read their illustrated story and hear their audio drama.

Ensemble stories — the cast together

Explore all the stories →

What next? Pick a door

Chosen from what this app is about. What you open is remembered on this device only.

📚 Books for NumberVerse

Read the story, print a workbook, or color the cast — free PDFs to read offline or print at home.

Browse all books →

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