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Sum-sum

Score = 42 + 16 = 58
With 1-8, the maximum score is more than 130 points
Take-take

Score = 55 - 35 = 20
With 1-8, the maximum score is more than 55 points
Take-sum

Score = 42 - 16 = 26
With 1-8, the maximum score is more than 70 points
Sum-take

Score = 12 + 24 = 36
With 1-8, the maximum score is more than 70 points
Choose two digits and arrange them to make two double-digit numbers. Now add your double-digit numbers. Now add your single digit numbers. Divide your double-digit answer by your single-digit answer. Try lots of examples. What happens? Can you explain it?
What do the digits in the number fifteen add up to? How many other numbers have digits with the same total but no zeros?