IMC 2004 Q6
6. In Niatirb they use Cibara numerals. These are the same shape as normal Arabic numerals, but with the meanings in the opposite order. So “0” means “nine”, “1” means “eight” and so on. But they write their numbers from left to right and use arithmetic symbols just as we do. So, for example, they use 62 for the number we write as 37.
How do the inhabitants of Niatirb write the answer to the sum which they write as 837 + 742?
- A 419
- B 580
- C 1579
- D 5317
- E 8420
Intermediate Mathematical Challenge 2004, Question 6. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: B 580
The sum is what we would write as 162 + 257 and this equals 419. However, in Niatirb it would be written 580.
Solution © UK Mathematics Trust, from the IMC 2004 solutions.