Cogito
Grade 5 Math · Chapter 8 · Lesson 3
The Coordinate Plane
Across first, then up.
10 problems · about 15 minutes · 5.G.A.1
What this lesson teaches
The child plots and reads ordered pairs on a coordinate grid and explains why order matters.
- The axes cross at the origin, (0, 0).
- An ordered pair says how far across, then how far up.
- (3, 5) and (5, 3) are different places.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsReview — The Volume Formula: Volume of a 7 by 3 by 2 box?
Answer 42
Why 42 cubic units.
Review — Measuring Volume by Counting Cubes: A box 4 by 4 by 2. How many cubes?
Answer 32
Why 32 cubic units.
Warm Up
Straightforward practice. Get the method working first.
4 problemsIn (6, 1), how far across do you go?
Answer 6
Why 6 across, then 1 up.
Which number comes first in an ordered pair?
Answer The across one.
Why The first number is always the across one.
In (5, 9), how far up do you go?
Answer 9
Why The second number.
In (0, 6), how far across do you go?
Answer 0
Why Straight up the axis.
Build It Up
The same ideas with more to keep track of.
2 problemsAre (2, 8) and (8, 2) the same place?
Answer No.
Why You saw both on the grid.
Are (4, 4) and (4, 4) reversed the same place?
Answer Yes. Both numbers are the same.
Why That is the only time it happens.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Across Number: In the pair (7, 2), how far do you go across?
Answer 7
Why 7 across, then 2 up.
The Origin: How far across is the origin?
Answer 0
Why The origin is (0, 0).