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'Arrow Arithmetic 1' printed from http://nrich.maths.org/
Emanuel has yet another set of solutions to
these 3 problems. He ignores the length of the arrows but uses the
direction! I suspect that completes the set of plausible solutions
We will ignore the length of an arrow in order to simplify the
problem. Basing on traditional number line an arrow pointing
upwards or to the right can represent a plus (+), and an arrow
pointing downwards or the left can represent a minus (-).
From above the answer for question 1 is 3.
The first arrow of question 2 can represent 0 because it is halfway
between +1 and 1.
The second arrow is -1 and the third also is 0 since its halfway
between 1 and -1.
The result for question 2 therefore is -1
The third question is actually -1 + 1 which is 0.
Can you now interpret Sam, Tim and Hannah's
solutions according to whether they pay attention to arrow length
and arrow direction or not?