Why do this problem?
offers students a chance to consolidate their
understanding of coordinates whilst challenging them to think
Demonstrate the problem to the class, either using the
interactivity, or with a grid drawn on the board.
Give students about 10 minutes to work on the problem, either at
computers, or on paper in pairs - taking it in turns to choose
where the giraffe is and give the distances. Pairs can keep score
of the number of guesses each student required to find the giraffe
- the one with the lowest total wins.
Ask the class to share efficient strategies/useful ideas. Encourage
the students to consider all the points that satisfy each
condition, and to look at the shape of this locus. Re-emphasise
that the problem is to develop a strategy to find the giraffe with
the minimum number of guesses.
Return to the computers/pairs to work on the suggested strategies.
Provide squared paper for rough jottings.
If students are familiar with coordinates in 4 quadrants, the game
can be an excellent context for practising these - working on paper
with suitable grids.
Which points satisfy the conditions given so far?
How can you narrow down the possibilities?
Play the game on a grid with axes from -9 to 9. Restrict the
guessing to the central square -5 to 5, but insist that the giraffe
is lost outside this central square. Students are allowed one
'final answer' guess outside the square to locate the
Encourage students to draw the situtation on squared paper, and
colour code points that are possible/impossible; looking at the
result of each new piece of information.