ROSECODE 341
Unreachable numbers
Using four numbers 4 and the 4 operations +, -, *, / we can build all numbers up to 9.
10 is the first not reachable
With four numbers 5 8 is the first not reachable
What are the first unreachable numbers when we use eight 4 and eight 5?
Answer format:
Example: 10,8
[My timing: 40 sec]
- 1 = ((4 + 4) - 4) / 4
- 2 = (4 / (4 + 4)) * 4
- 3 = ((4 + 4) + 4) / 4
- 4 = ((4 - 4) * 4) + 4
- 5 = ((4 * 4) + 4) / 4
- 6 = ((4 + 4) / 4) + 4
- 7 = (4 - (4 / 4)) + 4
- 8 = ((4 + 4) + 4) - 4
- 9 = ((4 / 4) + 4) + 4
- 12 = (4 - (4 / 4)) * 4
With four numbers 5
- 1 = ((5 + 5) - 5) / 5
- 2 = (5 / 5) + (5 / 5)
- 3 = ((5 + 5) + 5) / 5
- 4 = ((5 * 5) - 5) / 5
- 5 = ((5 - 5) * 5) + 5
- 6 = ((5 * 5) + 5) / 5
- 7 = ((5 + 5) / 5) + 5
- 9 = (5 - (5 / 5)) + 5
What are the first unreachable numbers when we use eight 4 and eight 5?
Answer format:
Example: 10,8
[My timing: 40 sec]