3. Solving
There is a total of 22 units + 34.
Since we know that they have 166
keychains all together, we can say that
22 units+34=160, thus
22 units= 166-34=132
1 unit =132/22=6
4. Solving
Susan has 1 units, Amy has 20 units
and Mary has 1 unit+34
Thus Susan has 6 key chains, Amy
has 6x20=120 key chains and Mary
has 6+34=40 key chains
5. Why this is inefficient
A lot of time if needed if the question
requires you to draw a large number
of units(such as 20 units in the
example)
Not as efficient as Algebra for solving
some of the tougher questions
