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.
a.   7 × 10 = _______
b.   100 × 7 = _______
c.   _______ = 7 × 1,000
d.   10 × 3 = _______
e.   1,000 × 30 = _______
f.   _______ = 10 × 30
g.   100 × 14 = _______
h.   _______ = 10 × 25
i.   54 × 1,000 = _______


aligns: no