Tiny Explorers · Ages 2 to 4
Caterpillar Crunch
Tap the caterpillar numbers in counting order to build number recognition for ages 2 to 4.
5 levels+40 XP
ProgressNot started
5 levels · BeginnerPlay
Tiny Explorers · Ages 2 to 4
All Tiny Explorers gamesPart Part Whole Boxes
Fill the missing box in a part, part, whole bar model to split totals up to 10, for ages 2 to 4.
BuilderPart part whole: split a total into two parts~8 min per level5 levelsAll devices
- Free · no account required
- COPPA compliant
- +10 XP per level
- 5 levels
- Plays on all devices
- Curriculum-aligned
The learning journey
Every activity is one step. Here is where this one fits.
- Play(you are here)Learn the idea in a game
- PractiseLock it in on paper
- ReviewCome back and keep it sharp
- MasterTake on a harder challenge
- AchieveEarn a certificate
About Part Part Whole Boxes
Part Part Whole Boxes uses the bar model that runs through primary maths teaching in the US, UK, Canada and Australia, introduced at the earliest point a child can meet it. Three boxes appear: two parts and the whole they make together. One box is empty, and the child taps it and then chooses a number to fill it from the small set offered. At the first level the empty box is always one of the parts, which is the easier direction — the whole is visible, one part is visible, and the missing part can be worked out by counting on. From the second level the whole itself can be the empty box, which asks the same fact the other way round and is exactly what a fact family means: five and two make seven, so seven take away two is five, and these are one piece of knowledge rather than two. Building that flexibility early is what makes number bonds stick, and it is the reason the bar model is drawn rather than the sum being written out. Totals grow from five at the first level to ten at the fifth, staying inside the range a kindergarten child is working in. Only a handful of numbers is offered to place at a time, so the choice is never overwhelming, and a wrong placement simply flashes and can be tried again with nothing lost. Every box and every number can be reached by tapping or with the keyboard alone, and each is announced clearly to screen readers. The game needs no sign-up, shows no advertising to children, and keeps progress on the device.
Where to go next
Chosen by the skills this activity practises.
Next — more of the same skill
Printable worksheets for this skill
A hand for grown-ups
- Before you start
- Have something countable nearby. Being able to check "3 and 2 really is 5" by counting builds trust in the maths.
- While they work
- If a sum is hard, suggest counting on from the bigger number rather than counting both from one. It is a real strategy, not a crutch.
- Afterwards
- Try one together out loud, talking through how you worked it out. Hearing an adult think aloud is genuinely useful.
- Watch out for
- Counting both numbers from one every time. Nudge gently towards "start at the bigger one and count on".
- Away from the screen
- Add up small shopping items, or dots on two dice. Board games with dice are addition practice in disguise.
How to play
A question appears on screen
A maths question is shown in large text at the centre of the play area. A timer bar begins counting down from 90 seconds.
Choose the correct answer
Answer options are shown as large buttons. Tap and drag, or use the mouse on desktop. Any input method works — touch, mouse or keyboard.
Build your streak
Each consecutive correct answer increases your streak. A longer streak lights up the flame icon and adds a bonus multiplier to the XP you earn for the level.
Finish the level
Each level has 5 questions. Complete them to earn the full level reward (+10 XP, plus up to +10 XP for a perfect run). Progress is saved locally and shown on the Parent Dashboard.
Curriculum alignment
Mapped to national curriculum frameworks so teachers and parents can match practice to school standards.
- United StatesCommon Core State Standards for Mathematics · number-bonds, fact-familiesAligned to number-bonds, fact-families number and operations objectives.
- United KingdomNational Curriculum for England — Maths · number-bonds, fact-familiesAligned to number-bonds, fact-families number and operations objectives.
- AustraliaAustralian Curriculum v9.0 — Mathematics · number-bonds, fact-familiesAligned to number-bonds, fact-families number and operations objectives.
- CanadaPan-Canadian Provincial Standards · number-bonds, fact-familiesAligned to number-bonds, fact-families number and operations objectives.
Common questions from parents & teachers
Everything you need to know before your child starts playing.
- It is three boxes showing two parts and the whole they make together. It is the earliest form of the bar model used throughout primary maths teaching.
- It is designed for children aged 2 to 4, and suits kindergarten and reception children working on number bonds within 10.
- Yes. At the first level a part is always missing. From the second level the whole can be missing instead, which practises the same fact in the other direction.
- Yes. Tap an empty box, then tap a number — or use Tab and Enter. There is no drag gesture anywhere in the game.
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