Schools

I had more then 4500 H schools and now its about 1500 . i didn't destroyed it so what happend?.

If you have not kept a sufficient amount of professionals/workers they will automatically shut down. Check your newspapers, if it didn't happen to long ago, it will appear in your newspapers.

One another question in my country
Expected Number of Births This Year 760,483
Expected Number of Deaths This Year 793,312

the Number of Births should be 2x more then Deaths isn't it ? Or is that because Back to Work Schools? and if thats so is there any way to destroy Back to Work Schools?

You can reduce the amount of Back to work Schools just like you put them to work, just enter a lower number instead of a higher one.
And those schools have no effect on births afaik. The Death:Birth Ratio mainly depend on your health index to some extend and on your population size, the bigger the Populationdensity the less people want more children.

i have 72,076,528 pops and my avrage Health index is 104

104 is not enough for a 72M population.

I think above 60M Population there are more deaths then births. If you have higher health index the higher the live expectancy of your pop will increase and the average age will increase, which will result in more workers living till their maximum 'working time' of age 65 which will increase your workforce but also will increase the number of pensioneers you will have which will increase your Social Costs