Positive 3, If You're starting at -6 and you add the first 6 it's at 0, now you have 3 more to add to make 9. And that gives you positive 3. or if you do 9 - 6 you can get your answer that way too.
Circle area equation is 3.14 x r squared.
So for question 1,
The radius is 3 cm.
We can square the radius ( 3 squared = 9).
After that, 9 x 3.14 = 28.26.
And after that we match our answers on the right hand column. Since we don't have the answer as given, we try to look for similar numbers. If we look at H, it shows us 0.2826 km squared. When cm is turned into km, the decimal moves two digits to its left. So for question 1, H is correct.
7.5, because:
Ex: .1, 1 is in the tenths place because it is right after the decimal. The digit after 5 is 0, and that rounds down. 0-4 round down, and 5-9 round up. So, 0 would keep 5 as itself.