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Need help on this counting

 

We call a number cozy if every digit in the number is either even or next to an even digit.  For example, a number is cozy if every digit in the number is either a 2 or next to a 2.  For example, the number 222, 72, 45, and 810 and are all cozy.  Also, the numbers 202 and 2772 are cozy.

 

How many 2-digit numbers are cozy?

 

How many 3-digit numbers are cozy?

 Feb 15, 2023
 #1
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The number of 2-digit cozy numbers is 75.

 

The nubmer of 3-digit cozy numbers is 810.

 Feb 15, 2023

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