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| page | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| number | 1 | 2 | 4 | 5 | 7 | 8 | 10 | |||
| = | = | +1 | +1 | +2 | +2 | +3 | +3 | +4 | +4 |
Add one to the difference for each odd page
89 is before 90, the 45th even number, so 89 is the 45th odd number
Difference has increased by 1 for every odd number except for 1
So number 89 + 45 = 133 is printed on the last page.