Riddles, one at a time
Glass Overlay: Lines Cancel
Which card completes the grid?
Lines that appear on both cards disappear; all the other lines stay.
Video · Expert
Challenge link
B
In each row, lines on both cards cancel and the rest stay. Row 3 gives card B.
Day After Tomorrow
Video · Easy
Challenge link
Wednesday
Two days back from Friday: Thursday, then Wednesday.
Longest Roman Year
Which year needs the MOST Roman letters?
Some digits need many letters: 8 is VIII, but 9 is just IX.
Video · Hard
Challenge link
1888
1888 = MDCCCLXXXVIII: 13 letters. 1777 needs 10.
Fewest Tokens: Pay 6
Which tokens pay 6 with the fewest tokens?
Biggest first is not always fewest. Try every pair.
Video · Medium
Challenge link
3 + 3
Just 2 tokens. Biggest first, 4 + 1 + 1, needs 3.
Mirror Odometer: 15951
How many more km until the next mirror number?
The middle digit is already 9, so it cannot go up. What has to change instead?
Video · Medium
Challenge link
110 km
The next mirror number is 16061: 16061 − 15951 = 110.