Hmm, I think it's possible to raise your IQ by practicing and applying certain thinking strategies. Especially given that IQ is an artificial measure of intelligence.
Most humans cannot get better at this easily at least. You can always try...
On working memory, I think the average is 7, or something like that, Try to remember a number in inversed order and see if you get past that to 9-10 that´s pretty hard to learn too
I remember the day our class was asked about a dice. I was the only know that knew by observation the response to which number was under the dice not being visible.
PS They always add up to seven
YMMV
I had dice as a kid that did not follow this rule.