The Dept of Education's annual budget is about $70 billion and has been in that range for several years. I did a thumbnail estimate based on that. In fact the accumulated cost might be considerably higher.
The decline in literacy and math scores is well documented.
That is all very well, but could you provide references for the cost (including any programs it replaced) and the downward progression in literacy and maths in the USA since 1979?
edit - Just looked at budgets. You are picking the peak. Which makes me somewhat doubtful of the rest of your analysis. In 2009 it was $32 billion. In 2010 it was $56 billion. It peaked at $71 billion in 2011 and has been almost flat since then.
Appropriations since 1980 add up to about $1.334 trillion. This is not inflation adjusted, however, so the equivalent amount in 2014 dollars would be much higher.
I wish they had given NASA that money instead and maybe we'd have a colony on the moon by now.
You have to factor in the cost of the programs it replaced, given it was largely created by transferring education programs from other government departments.
Also, you have given no references whatsoever for your claimed steady decline in literacy and maths since 1979.
The decline in literacy and math scores is well documented.