Chapter 4.5, Problem 16P

While working on the multiplication problem 38 . 25, Maria says this:

Four times 25 is 100, so 40 times 25 is 1000. Now take away 2, so the answer is 998.

Is Maria’s method correct or not? If it is correct, write equations that incorporate Maria’s work and that show why it’s correct. If Maria’s reasoning is not correct, work with portions that are right to correct Maria’s work, and write a string of equations that corresponds to your corrected method for calculating 38 25. Write your equations in the following form:

   $\begin{array}{l}\begin{array}{l}\\ 38.25=someexpression\end{array}\hfill \\ \begin{array}{l}=someexpression\\ =:\\ \end{array}\hfill \end{array}$