Marek added four consecutive two-digit numbers and rounded the result to the tens. Jirka took the same numbers, first rounded them to the tens, and then added them. His result was ten greater than Marek's. Which numbers did the boys add if their results were less than 100? Find all possible solutions.
Let's try all the quadruples that come to mind one by one

| Numbers | Mark's result | Jirka's result |
| :---: | :---: | :---: |
| $10,11,12,13$ | 50 | 40 |
| $11,12,13,14$ | 50 | 40 |
| $12,13,14,15$ | 50 | 50 |
| $13,14,15,16$ | 60 | 60 |
| $\mathbf{1 4 , 1 5 , 1 6 , 1 7}$ | 60 | 70 |
| $\mathbf{1 5 , 1 6 , 1 7 , 1 8}$ | 70 | 80 |
| $\mathbf{1 6 , 1 7 , 1 8 , 1 9}$ | 70 | 80 |
| $\mathbf{1 7 , 1 8 , 1 9 , 2 0}$ | 70 | 80 |
| $18,19,20,21$ | 80 | 80 |
| $19,20,21,22$ | 80 | 80 |
| $20,21,22,23$ | 90 | 80 |
| $\ldots$ |  |  |
| $24,25,26,27$ | 100 | 110 |

Four possible solutions are marked in the table in bold. For larger numbers, the result of the mathematical operations will be greater than or equal to 100.

[1 point for deciding to solve the problem systematically by searching, -1 point for determining the "extreme" quadruples with the smallest and largest numbers, -1 point for each solution]