standard_description: Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900.
problem_activity: Problem 1
Solve.
a.
$$380\div10=$$
________
b.
$$4,820 \times \frac{1}{10}=$$
________
Problem 2
Explain what happened to the value of the 8 in both problems in #1.


aligns: no