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It is not exactly rocket science to understand that people get better at doing something with training (although it is almost brain surgery to understand why this happens). Not everyone can learn to play chess like Garry Kasparov, but almost everyone can learn to play it quite well, with enough training.

The same is true for abstract reasoning, solving arithmetic or geometric problems, understanding your mother tongue, and other factors that influence IQ. If you spent ten years learning to see relations in sequences of numbers, you would be able to recognize many more of these much faster than someone who never did so, just like experienced chess players are able to recognize many more tactical and strategic ideas than beginners, no matter how much talent they have.
All the skills that constitute IQ can be further developed with training. We are not all equal in terms of how fast or how far we can develop these skills, but we can all develop them to a certain degree.

Bellow you can see timeline of your IQ Progress.