standard_description: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
problem_activity: Solve. Show or explain your work.
a.   4.62 ÷ 0.07
b.   51.2 ÷ 0.08
c.   2.91 ÷ 0.6


aligns: no