Problem-Solving Strategies
Write the facts down first, then pick the strategy that fits and follow it step by step: when you know the end and need the start, work backwards from the last step.
Problem-Solving Strategies: Working Backwards
Methods in this video
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- 1
Undo the last step first
When to use it: A number machine, flow chart or number rule gives the result and asks for the input. One branch may already be known. You may need to undo mistaken steps before doing the correct ones.
- Write the operations in order. Start at the result and undo the last step first.
- Check which number is added, subtracted or divided. Use the inverse operation. Work out any known branch first.
- Count the backward steps. Check by going forwards, then give the digit sum or corrected result if asked.
Practise exam-style questions with these methods
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