This one will be the last in the Roman numeral theme for a bit. But if you want more just message me and I can add more into the queue. This one, CXIX + XI = CXXX has a lot of solutions! You might be able to intuitively just guess what solutions look like. All 72 solutions are show after the image.
SPOILER SOLUTIONS!
| CXIX_first | XI_second | CXXX_third |
|---|---|---|
| 1202 | 20 | 1222 |
| 1303 | 30 | 1333 |
| 1404 | 40 | 1444 |
| 1505 | 50 | 1555 |
| 1606 | 60 | 1666 |
| 1707 | 70 | 1777 |
| 1808 | 80 | 1888 |
| 1909 | 90 | 1999 |
| 2101 | 10 | 2111 |
| 2303 | 30 | 2333 |
| 2404 | 40 | 2444 |
| 2505 | 50 | 2555 |
| 2606 | 60 | 2666 |
| 2707 | 70 | 2777 |
| 2808 | 80 | 2888 |
| 2909 | 90 | 2999 |
| 3101 | 10 | 3111 |
| 3202 | 20 | 3222 |
| 3404 | 40 | 3444 |
| 3505 | 50 | 3555 |
| 3606 | 60 | 3666 |
| 3707 | 70 | 3777 |
| 3808 | 80 | 3888 |
| 3909 | 90 | 3999 |
| 4101 | 10 | 4111 |
| 4202 | 20 | 4222 |
| 4303 | 30 | 4333 |
| 4505 | 50 | 4555 |
| 4606 | 60 | 4666 |
| 4707 | 70 | 4777 |
| 4808 | 80 | 4888 |
| 4909 | 90 | 4999 |
| 5101 | 10 | 5111 |
| 5202 | 20 | 5222 |
| 5303 | 30 | 5333 |
| 5404 | 40 | 5444 |
| 5606 | 60 | 5666 |
| 5707 | 70 | 5777 |
| 5808 | 80 | 5888 |
| 5909 | 90 | 5999 |
| 6101 | 10 | 6111 |
| 6202 | 20 | 6222 |
| 6303 | 30 | 6333 |
| 6404 | 40 | 6444 |
| 6505 | 50 | 6555 |
| 6707 | 70 | 6777 |
| 6808 | 80 | 6888 |
| 6909 | 90 | 6999 |
| 7101 | 10 | 7111 |
| 7202 | 20 | 7222 |
| 7303 | 30 | 7333 |
| 7404 | 40 | 7444 |
| 7505 | 50 | 7555 |
| 7606 | 60 | 7666 |
| 7808 | 80 | 7888 |
| 7909 | 90 | 7999 |
| 8101 | 10 | 8111 |
| 8202 | 20 | 8222 |
| 8303 | 30 | 8333 |
| 8404 | 40 | 8444 |
| 8505 | 50 | 8555 |
| 8606 | 60 | 8666 |
| 8707 | 70 | 8777 |
| 8909 | 90 | 8999 |
| 9101 | 10 | 9111 |
| 9202 | 20 | 9222 |
| 9303 | 30 | 9333 |
| 9404 | 40 | 9444 |
| 9505 | 50 | 9555 |
| 9606 | 60 | 9666 |
| 9707 | 70 | 9777 |
| 9808 | 80 | 9888 |