In a country far away the currency is not based on the normal system of 100 cents to the dollar (or whatever) and not even on the twelve pennies to the shilling and 20 shillings to the pound in pre-decimal Sterling. Instead they have Tads, Bits and Crowns, and the following sum is correct.
| Crowns | Bits | Tads | |
| 3 | 7 | 5 | |
| 2 | 13 | 7 | |
| 7 | 6 | 7 | |
| 8 | 11 | 6 | |
| Total | 22 | 12 | 1 |
So how many Tads are in a Bit and how many Bits are in a Crown?
If you add up the Crowns column there are 20, which means that there must be a carry of two from the Bits column to make 22.
The Tads column adds up to 25, but only one is recorded, so the number of Tads in a bit must divide exactly into 24. And it must be at least eight as there is a seven in the Tads column. That is, eight, twelve or 24.
Finally, there are at least 14 Bits in a Crown as there is a 13 in the Bits column.
A little trial and error gives eight Tads to the Bit and 14 Bits to the Crown.