#17 Which flipping year?
2019 is an example of a year that can be “flipped”. This means that on an old-style calculator display, it still forms a four-digit number when spun both horizontally and vertically:
The difference between a flippable year and its flipped version is called the flipping difference, and for 2019 the flipping difference is 6102 – 2019 = 4083.
Since the Romans conquered Britain in AD 43, which year has had the biggest flipping difference?
Answer next week
#16 Clever code
Solution
The 10-digit code is 6210001000
Rashmi’s codes are self-describing numbers. Each digit in order gives the number of 0s, 1s, 2s, 3s and…
