SPACE ACADEMY · TRY, THINK, PLAY

Class 4: Measure the mission

Read scales and rulers, compare like units and infer unknown measurements.

Play missionChapters

Try a quick challenge

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

ExploreMeasurement and conversions

The pans in Isha's balance are level. How many grams does one crate weigh?

2 identical crates on a level balanceKMK = 50 gM = 170 g
  1. 110
  2. 170
  3. 60
  4. 120
Need a hint?

Subtract the extra weight before sharing the remaining mass equally among the crates.

Answer & method
Answer C: 60

(170 - 50) / 2 = 60 g per crate.

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ReasonMeasurement and conversions

Dev saw the temperature rose by 11 degrees after this reading. What was the new temperature in degrees C?

Lab thermometer: degrees C1014182226
  1. 11
  2. 22
  3. 12
  4. 33
Need a hint?

Find the value of one scale interval before following any change.

Answer & method
Answer D: 33

The thermometer reads 10 + 6 x 2 = 22 degrees C. Apply the change: 22 + 11 = 33.

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StretchMeasurement and conversions

Noor uses the second amount, then splits the remainder into 2 equal shares. How much is each share in g?

Measurement logFirst amount4 kg 800 gAmount used2 kg 600 g1 kg = 1000 g
  1. 7400
  2. 2000
  3. 2200
  4. 1100
Need a hint?

Rewrite both entries in the smaller unit before combining or sharing them.

Answer & method
Answer D: 1100

4 kg 800 g = 4800 g; 2 kg 600 g = 2600 g. 4800 - 2600, then divide by 2, gives 1100 g.

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For grown-ups

Ideas to practise

  • Measurement and conversions. Use the same unit before adding or comparing measurements.
  • Working backwards. Undo the last operation first, then undo the earlier operation.
  • Coding and decoding. Apply the stated code consistently to each letter.

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 Survey telescope 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.

  • Add or subtract measures in mixed units
  • Share a measure equally or count equal portions
  • Measure between non-zero ruler marks
  • Read a thermometer and a temperature change
  • Find one mass on a balanced scale
  • Combine mixed units in a laboratory log
Play Explore

Reason

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

  • Add or subtract measures in mixed units
  • Find what is left after filling equal packs
  • Share a measure equally or count equal portions
  • Measure between non-zero ruler marks
  • Read a thermometer and a temperature change
  • Find one mass on a balanced scale
  • Combine mixed units in a laboratory log
  • Find the mass of shapes from three weighing scales
Play Reason

Stretch

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

  • Add or subtract measures in mixed units
  • Find what is left after filling equal packs
  • Share a measure equally or count equal portions
  • Find one mass on a balanced scale
  • Combine mixed units in a laboratory log
  • Measure between non-zero ruler marks
  • Find the mass of shapes from three weighing scales
  • Infer a rule from input and output pairs
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.

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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.

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