4. feladat megoldása
| – | 1 | 5 | + | 2 | 4 | – | 9 | + | 1 | 8 | – | 3 | 2 | = | 4 | 2 | – | 5 | 6 | = | – | 1 | 4 |
| 4 | 8 | – | 3 | 2 | + | 2 | 7 | + | 2 | 1 |
+ | 2 | 9 | = | 2 | 9 | – | 3 | 2 | = | – | 3 | |
| + | 2 | 7 | – | 3 | 8 | + | 5 | 4 | – | 2 | 7 | + | 4 | 1 | = | 9 | 5 | – | 3 | 8 | = | 5 | 7 |
| 2 | 1 | – | 1 | 7 | + | 2 | 9 | + | 5 | – | 1 | 2 | – | 2 | 1 | = | 3 | 4 | – | 2 | 9 | = | 5 |
| – | 3 | + | 1 | 7 | – | 2 | 7 | + | 4 | 2 | – | 3 | 0 | + | 9 | = | 6 | 8 | – | 6 | 0 | = | 8 |