Start in the bottom left corner and move either up or right, one square at a time, using the numbers and the mathematical signs along the way. What is the largest total you can make?
+
2
−
4
+
2
2
+
2
−
2
+
−
1
+
3
−
3
2
−
3
+
1
−
+
1
−
3
+
2
3
+
3
−
2
+
Note: this puzzle is not interactive, and the numbers cannot be clicked.
Hint
We'll assume that we can actually fold it this many times.
Answer
Very thick indeed! The paper doubles in thickness with each fold. If we could fold it 50 times, it would be around 70 million miles thick!
1 fold would be 0.1 + 0.1 = 0.1 x 2 ^ 1 = 0.2 mm
2 folds would be 0.1 + 0.1 + 0.1 + 0.1 = 0.1 x 2 ^ 2 = 0.4 mm
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10 folds would be 0.1 x 2 ^ 10 = 102.4 mm
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50 folds would be 0.1 x 2 ^ 50 = 112,589,990,684,262.4 mm = 112,589,990.7 km (around 70 million miles).
