The answer for that would be: 4+.02+.09
I tried to include some explanations as well. Hopefully this helps.
12.9 i think, not sure. try it though
The <span> answer is 6.75. Since if you divide the number by 8 you get 6.75.</span>
20 + 4 + 3/10 + 5/100 + 7/1000