Keep number equations balanced
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Log in to continueUse inverse operations and properties to find unknown values.
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3 × □ = 18. What number belongs in the box?
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Answer: 6
- Identify which quantity is unknown.
- The missing value is 6; place it in the box and check the original equality.
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Curriculum reference
Victorian Curriculum F–10 Version 2.0
Pi Leo practice scope
Use inverse operations and properties to find unknown values.
Read the official VCAA curriculum description (VC2M5A02)
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- Supported by the guided activity; selecting an MCQ does not demonstrate this action.
- VC2M5A02-C01A missing factor is found by division. A missing dividend is divisor × quotient. For a missing divisor, divide the known whole by its quotient. Identify the role of the box before choosing an operation.
- VC2M5A02-C02An equals sign says the two sides have the same value. Simplify the fully known side first, then recover the missing quantity. For example, 3 × □ = 12 + 9 gives 3 × □ = 21, so □ = 7.
- VC2M5A02-C03Treat a bracket as one quantity. Undo the outside operation first, then the operation inside the bracket. Put the answer back into the original equation to check both sides, rather than checking only your last calculation.
- VC2M5A02-C04Constructing equivalent numerical equations and explaining the properties used.
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- D01Locate the unknownA missing factor is found by division. A missing dividend is divisor × quotient. For a missing divisor, divide the known whole by its quotient. Identify the role of the box before choosing an operation.
- D02Balance the two sidesAn equals sign says the two sides have the same value. Simplify the fully known side first, then recover the missing quantity. For example, 3 × □ = 12 + 9 gives 3 × □ = 21, so □ = 7.
- D03Work backwards and checkTreat a bracket as one quantity. Undo the outside operation first, then the operation inside the bracket. Put the answer back into the original equation to check both sides, rather than checking only your last calculation.