ตัวเลขมหัศจรรย์.... จำนวนที่ลงท้ายด้วย 199
| 901 |
* |
99 |
= |
89199 |
| 9001 |
* |
999 |
= |
8991999 |
| 90001 |
* |
9999 |
= |
899919999 |
| 900001 |
* |
99999 |
= |
89999199999 |
| 9000001 |
* |
999999 |
= |
8999991999999 |
| 90000001 |
* |
9999999 |
= |
899999919999999 |
| 900000001 |
* |
99999999 |
= |
89999999199999999 |
| 9000000001 |
* |
999999999 |
= |
8999999991999999999 |
| 90000000001 |
* |
9999999999 |
= |
899999999919999999999 |
| 900000000001 |
* |
99999999999 |
= |
89999999999199999999999 |
| 9000000000001 |
* |
999999999999 |
= |
8999999999991999999999999 |
| 90000000000001 |
* |
9999999999999 |
= |
899999999999919999999999999 |
ที่มา เด็กดีดอทคอม