Answer:
1.0*10^(-1) (but 0.10 would also be appropriate)
Explanation:
Rewrite 35.83 x 0.0028 as 3.583*10^1 and 0.0028 as 2.8*10^(-3).
Estimate the product: 36 times 3 is 108.
Multiply 3.583 and 2.8 together, obtaining 10.0324.
Noting that 10^1 * 10^(-3) = 10^(-2), write the intermediate answer as:
10.0234*10^(-2).
Move the decimal point one place to the left, and then, in compensation, rewrite this expression as 1.0234*10^(-1).
Finally, rewrite this result as 1.0*10^(-1). Since 0.0028 has just 2 signficant figures, 1.0 (2 significant figures) is appropriate. That's 1.0*10^(-1).