Puzzle of the week

There are two sequences of natural numbers. The first sequence consists of all natural numbers that do not contain a particular digit, in ascending order. The second sequence consists of all the remaining natural numbers in ascending order. Every natural number occurs exactly once in exactly one of the sequences.

How many terms are there in the first sequence such that each of those terms is greater than the corresponding term at the same position in the second sequence?

[UNSOLVED]

Random puzzle from the past

The product of the tens digits of a few given perfect squares is odd. What is the units digit of the product of these perfect squares?

[SOLVED]

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