Did you solve it? Nick Berry, data dude

The solutions to today's questions

Earlier today I set you these three problems from Nick Berry's fabulous DataGenetics blog. Nick died last week aged 55, as I wrote about in the original post.

1. No-zero heroes

If he selects two odd numbers, the absolute difference between two odd numbers is always an even number. What has happened is that the quantity of odd numbers remaining has been reduced by two.

If he selects two even numbers, the absolute difference between a pair of even numbers is also even. The quantity of odd numbers remaining stays the same.

If he selects an odd and an even number, the absolute difference between this pair is odd. We lost one odd number, but gained a new one, so the quantity of odd numbers remaining stays the same.