Use constant difference to balance equations and find unknowns
I can use the same difference rule to balance equations.
Use constant difference to balance equations and find unknowns
I can use the same difference rule to balance equations.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- If I add __ to the minuend and add the same number to the subtrahend, the difference stays the same.
- If I subtract __ from the minuend and add the same number to the subtrahend, the difference stays the same.
- A number line can be used to represent the 'same difference' generalization.
Keywords
Minuend - The minuend is the number being subtracted from.
Subtrahend - A subtrahend is a number subtracted from another.
Difference - The difference is the result after subtracting one number from another.
Constant - A constant is a quantity that has a fixed value that does not change or vary, such as a number.
Unknown - An unknown is a quantity that has a set value but it is represented by a symbol or letter.
Common misconception
Lots of pupils will want to calculate the value of the expression with the known parts in order to calculate the unknown part without considering a more efficient approach.
Calculating the value of one expression is efficient with simple numbers but encourage the children to try and compare the parts instead. As the numbers get harder, calculating the expression becomes much less efficient.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
6 Questions
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