Projectors, videos, computers, tablets, calculators, are all completely useless in teaching math.
In the USA there are approximately 50 million students aged 5-18. If you paid for each student to get 1:1 attention one day a week, you would need one teacher per five students in schools that meet five days a week. Let's use that number because it reduces 50 million students nicely to 10 million teachers. Let's pay each teacher $70K/year. That would cost $700 billion per year.
The USA military spent $100 billion per year in Afghanistan.
If the USA provided the 1:1 attention only in 1st Grade and 3rd Grade, they could fund it with the same commitment they made in Afghanistan with a lot fewer deaths. The USA persisted in Afghanistan for 20 years. Shall we experiment with education for 10 years and see if we get a better result than we did in Afghanistan?
That 100 billion goes to a bunch of extremely well-connected businesses who fund lobbyists to make sure the USA continues expending munitions in a series of utterly pointless, futile, wars.