Step by step
The question
Question: find the midpoint of (5, −1) and (−5, −3).
1 Plot the points
Draw the grid.
Put both points on the grid: (5, −1)
and (−5, −3).
Join them with a straight line.
We want its middle.
2 Middle of the x's
The midpoint is halfway across.
Halfway between two numbers: add them, then divide by 2.
Adding a negative is the same as taking away.
5 plus −5 is 0.
0 divided by 2 is 0.
So x = 0.
3 Middle of the y's
Now the y's: the same.
Add them, then divide by 2.
Adding a negative is the same as taking away.
−1 plus −3 is −4.
−4 divided by 2 is −2.
So y = −2.
4 The midpoint
So the midpoint is M = (0, −2).
Put M on the grid.
It sits on the line, right in the middle.
5 Check
Let's check on the grid.
From (5, −1) to M:
we go left 5, down 1.
From M to the other point:
we go left 5, down 1.
The same moves.
So M is exactly in the middle!
Let's look back.
First: plot the points.
Then: middle of the x's.
Then: middle of the y's.
Then: the midpoint.
Last: check.