SPACE ACADEMY · TRY, THINK, PLAY

Class 4: Mission mathematics

Interpret models, find unknown amounts and link operations instead of only calculating a total.

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Try a quick challenge

Just a quick try. Not saved; no game rewards.

ExploreEqual groups and multi-step problems

A school has 49 classrooms with 3 desks in each classroom. How many desks are there altogether?

  1. 157
  2. 196
  3. 117
  4. 147
Need a hint?

Multiply by the ones, then by the tens, and add the two partial products.

Answer & method
Answer D: 147

49 × 3 = 147.

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ReasonEqual groups and multi-step problems

A school has 54 classrooms with 20 desks in each classroom. How many desks are there altogether?

  1. 1080
  2. 880
  3. 1026
  4. 1134
Need a hint?

Multiply by the ones, then by the tens, and add the two partial products.

Answer & method
Answer A: 1080

54 × 20 = 1080.

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StretchEqual sharing

A number is divided by 22. The quotient is 197 and the remainder is 10. What is the number?

  1. 4354
  2. 4334
  3. 4324
  4. 4344
Need a hint?

Multiply the divisor and quotient, then add the remainder.

Answer & method
Answer D: 4344

22 × 197 = 4334. Add 10: 4344.

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For grown-ups

Ideas to practise

  • Equal groups and multi-step problems. Find the total in equal groups before applying the next change.
  • Equal sharing. Divide into equal groups. Check by multiplying your answer by the number of groups.
  • Addition and missing amounts. Combine the amounts, or work backwards from the total.
  • Subtraction and change. Start with the original amount and take away what was used.
  • Working backwards. Undo the last operation first, then undo the earlier operation.

A game mission has 8 untimed questions. Only the game saves choices and hints. A finished mission earns one launch charge and participation towards the Transfer tug in Nebula Research Station. The chapter goal is 8 different questions in finished sets; hints and wrong answers count as participation, not mastery. Some craft systems link more than one chapter.

Choose a level

Explore

Foundations: read a representation and practise the underlying idea.

  • Solve a multiplication story with a hidden step
  • Pack items into bags and find what is left
  • Find a total in a multi-step story
  • Use the quotient and remainder of a division
  • Complete a multiplication area model
  • Interpret packing remainders
  • Recover a missing column digit
Play Explore

Reason

Paper-style reasoning: connect clues, interpret a diagram or work backwards.

  • Solve a multiplication story with a hidden step
  • Pack items into bags and find what is left
  • Find a total in a multi-step story
  • Find two numbers from their sum and difference
  • Use the quotient and remainder of a division
  • Find prices or masses from two or three combined totals
  • Complete a multiplication area model
  • Interpret packing remainders
  • Recover a count from comparison bars
  • Recover a missing column digit
Play Reason

Stretch

Higher-order practice: link conditions, test statements and avoid a tempting wrong method.

  • Find a total in a multi-step story
  • Find two numbers from their sum and difference
  • Solve a letter multiplication puzzle
  • Use the quotient and remainder of a division
  • Find prices or masses from two or three combined totals
  • Recover a count from comparison bars
  • Solve a multiplication story with a hidden step
  • Recover a missing column digit
  • Interpret packing remainders
Play Stretch

Levels change representations, clues and conditions, not just the numbers. These are practice formats, not validated exam-equivalent difficulty.

Using the feedback

Learning reports distinguish hinted answers from independent first choices. They consider up to 20 recent different, unhinted questions per skill and level, and wait for at least five before suggesting extra practice. Repeating the same question does not add evidence. Reports are practice evidence, not IQ scores, diagnoses, ranks or predictions of competition results.

Ask the learner to explain a drawing or check with objects too. Choose Explore or an earlier chapter when a step feels too large.

Sources & limits

The grade topics use SOF IMO Class 4 published topic syllabus as their primary reference. The SOF sample and CREST previous-year paper below informed representations and reasoning demands. Providers have different topic boundaries; their syllabi are not interchangeable.

Questions, diagrams, picture choices, hints and explanations are original Otterly work, not copied paper questions or publisher artwork. No Olympiad provider is affiliated with or endorses Space Academy. This is not complete exam preparation; follow classroom teaching and check the current official syllabus too. Independent educator review is still needed for difficulty and breadth.

Content and coverage notes. To report a confusing question, describe the grade, chapter, level and question on the contact page. Do not send children’s personal information.

Private, local saves

Game progress stays only in this browser, in three anonymous explorer slots. Clearing site data or closing a private session may remove it. Download a private backup from Help & saves; there is no cloud sync. The game checks saves before play and stops on save failures rather than pretending progress was saved.

These page examples never change a saved game. Game links carry question settings, not a learner’s answers. There are no names, school details, public profiles, chat, analytics or advertising SDKs in the game. Grown-up guidance · Privacy

Original Otterly practice, not an official exam. Game progress stays on this browser.