If you are trying to find h, then its very simple.
So lets see 5+7=12
So 17-12=5
So lets check to see if h=5
5+5+7
5+5=10+7=17 so h is 5. :)
I don't know which one is underlined so I will write it out in words.
One million seven hundred and eleven thousand and seven hundred ninety-nine.
Hope I helped :)