# Fire at These Coordinates

In this Remarkable Idea, students will work on plotting points on a graph, and eventually determining the slope of a line from two points on a graph.

• Cause and effect
• Critical thinking
• Math
• Alternative methods of access

What you need:

Preparation:

1. Record the word “negative” to the TalkingBrix
2. Record “Y =” to the TalkingBrix
3. Record the numbers 0-5 on the Step-by-Step
4. Create overlays using the AbleNet Symbol Overlay Maker app.

What to do:

Level 1
In this level, students are trying to sink ships that exist in either perpendicular or horizontal line segments.
1. Each student will get a small piece of graph paper. The “target area” should be 5 points in each direction (100 possible coordinates).
2. Place a divider between students if they are seated near each other.
3. Students begin by placing their ships in either 2 dot line segment, 3 dot line segment, and 4 dot line segment. Students can use the TalkingBrixand Step-by-Step to assist with placement by giving coordinates (ex. the coordinate (-3,2) would be given by hitting the TalkingBrix to say the number is negative, then step through the Step-by-Step until the number 3 is reached. For the number 2, the student will cycle through the Step-by-Step until they come to the number 2.)
4. Begin the assault. Each student takes a turn choosing a coordinate to attack. Students use the TalkingBrix and Step-by-Step to give coordinates.
5. Students continue to guess coordinates until all of the ships have been sunk. The ships must be hit on all of their points to sink.

Level 2

In this level, students are trying to sink one ship that exists in a diagonal, horizontal, or vertical line.
1. In order to win, the students must give the slope-intercept formula for the line. The slope of the lines should be limited to a numerator/denominator no greater/less than (-)2 or (-)3 or the game could last extremely long.
2. Each student will get a small piece of graph paper. The “target area” is should be 5 points in each direction (100 possible coordinates).
3. Place a divider between students if they are seated near each other.
4. Students begin by placing their ship (1 line, slope numerator/denominator no greater than (-)2 or (-)3.) Students can use the TalkingBrix and Step-by-Step to assist with placement by giving coordinates (at least 2 from their line) or they can give their equation using the TalkingBrix and Step-by-Step.
Example: y = ½ - 3 would be:
TalkingBrix: Y=
Step-by-Step: 1
Step-by-Step: 2
TalkingBrix: negative
Step-by-Step: 3
5. Begin the assault. Each student takes a turn choosing a coordinate to attack. Students use the TalkingBrix and Step-by-Step to give coordinates.
6. Students continue to guess coordinate until one of them thinks they have found their opponents line and can give it in slope-intercept form. To initiate this process they will hit the “Y =” TalkingBrix. If the student is incorrect they lose a turn, if they are correct the game is over.

Tips to speed up games:
Tell each student which quadrants are empty on their opponents graphs (mention this may happen before the game begins, it may change their strategy). You do not have to tell students which quadrant is which (they should already know that anyway).

You may wish to make one hit on a ship be enough to sink it.