Answer:
See below.
Step-by-step explanation:
Draw a number line and draw points corresponding to -1, 0, and 1.
Mark 6 equal divisions between -1 and 0. Mark 6 equal divisions between 0 and 1.
Now you have the units between 1 and 0 and between 0 and -1 divided into sixths.
Now look at the point that corresponds to 1/2. It is the middle one-sixth mark between 0 and 1. Start there. That is 3/6 which is the same as 1/2.
You need to go 2/3 of a units to the left of 1/2.
2/3 = 4/6, so starting at 1/2, go 4 one-sixth marks to the left.
Now you are 2/3 unit to the left of 1/2.
See the number line below.
-1 0 1
<----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+------>
Start with a mark on 1/2, S in bold below.
-1 0 1/2 1
<----+---+---+---+---+---+---+---+---+---+---+---S---+---+---+---+---+------>
Now go 2/3 unit to left. 2/3 = 4/6, so go 4 one-sixth divisions to the left.
The point labeled with a bold E is the result. It is -1/6
-1 -1/6 0 1/2 1
<----+---+---+---+---+---+---+---E---+---+---+---S---+---+---+---+---+------>
(so called common ratio):
