Answer:
56 trees will make 10000 newspapers.
Explanation:
Given:
One tree makes approximately 230 newspapers.
Now, for estimating how many newspapers will be made with 56 trees.
By multiplying 
 trees with
 trees with 
 newspapers we get,
 newspapers we get,
 
 .
.
And, rounding 
 to one significant number (1 S.F.) is
 to one significant number (1 S.F.) is 
 .
.
Therefore, 56 trees will make 10000 newspapers.