The summer before 11th grade, my father decided he had enough. It was time to learn math, Soviet style. He sat me down for a few hours each morning with problems from 6th and 7th grade Russian math textbooks - which was strange to me of course because I was about to start 11th grade. One important rule was that a calculator was not allowed.
Everyday he had a list of questions ready for me that he had judiciously picked. Back in Ukraine he was a regional physics Olympiad winner, and a gold medal winner (in the Soviet Union, the top graduates from each high school were awarded a gold medal - goes to show how they valued academics I suppose). I can pull up some photos if anyone is interested.
The questions were very clever and pedagogical. You developed intuition by solving them. And you couldn't solve them if you didn't understand the underlying principles. And of course, there's the word problems. I could barely read Russian at the time, so I had to take my time, but they bridge the gap between theory and application. And without a calculator, you are forced to develop techniques for manipulating equations and numbers. You get really good at it.
I aced math and physics for the rest of high school (and later graduated with a degree in Engineering Physics).
The western education system really fails us. My dad sitting me down with those elementary Russian math textbooks and enforcing a no calculator rule was one of the best things he could have ever done for me. The Soviet mathematic curriculum was designed by some brilliant mathematicians who understood the importance of developing intuition. That importance seems to be lost here. People think that quantitative intuition doesn't matter as long as you can plug your equation into Wolfram Alpha. But when you approach math that way, you don't develop an analytical and quantitative lens.
Photos: [My father and my grandmother on the way to university in the 80s - https://photos.app.goo.gl/Tgv2gpy428rKs2GS8
Gold medal - https://photos.app.goo.gl/KsisSEvb4fbNEE419
Physics Olympiad diploma with translation - ]https://photos.app.goo.gl/b3hw6HXmQN25iXay9]