Maths Riddle - 2

[Deepak Kiran]

I have a calculator that can display ten digits. How many different ten-digit numbers can I type using just the 0-9 keys once each, and moving from one keypress to the next using the knight’s move in chess? (In chess, the knight move in an L-shape — one square up and two across, two squares down and one across, two squares up and one across, and other like combinations)

 

[URum]

You can form the numbers 5034927618 and 5038167294. You can also form their reverses: 8167294305 and 4927618305. Hence four different numbers can be made. The key point is to realize that the number must start or end on the ‘5’ key, followed/preceded by the ‘0’ key,

 

[Pr vino]

I have a calculator that can display ten digits. How many different ten-digit numbers can I type using just the 0-9 keys once each, and moving from one keypress to the next using the knight’s move in chess? (In chess, the knight move in an L-shape — one square up and two across, two squares down and one across, two squares up and one across, and other like combinations)

40320 ..8*7*6....*1 -40320..u like a factorial right