Question

1+2+3+4+5+6+7+8+9
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Answer 1

Answer:

Solution = 45.

I hope this answer is useful for you.

Answer 2

Answer:

(1+2)+(3+4)+(5+6)+(7+8)+9

3+7+11+15+9

(3+7)+(11+15)+9

10+26+9

(10+26)+9

36+9

45