Question

for each part, use all of the digits 5 6 7 8 9 once each and no other digits. show working to explain your answers.

what is the largest positive integer you can make from a calculation using only subtraction?

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I was confused as to how to answer this question - do I use the numbers once each in the entire equation (e.g. 567 - 89), or am I just not allowed to repeat them in the same number? (e.g. 98765 - 56789)

Answer 1

If I interpret your question correctly, ...

since all the digits have to be used, we will simply subtract the smallest
possible from the largest remaining, that is
9876 - 5 = 9871

Answer 2

thank you!