The numbers on blue shapes are the sums of the two hidden numbers on red circles at the ends of the lines. What are the hidden numbers?
Topics: Starter  Arithmetic  Problem Solving  Puzzles  Simultaneous Equations
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Note to teacher: Doing this activity once with a class helps students develop strategies. It is only when they do this activity a second time that they will have the opportunity to practise those strategies. That is when the learning is consolidated. Click the button above to regenerate another version of this starter from random numbers.
How difficult would the Pentadd puzzle be without the diagram? Imagine five numbers, randomly chosen, are added together in pairs to produce the following ten sums in no particular order. Can you figure out what those five numbers were?
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