Introduction
When playing the computer game "Number Between" Brad shows that he thinks 0.45 is forty five tenths, so must be larger than 0.5 (five tenths). The puzzling feedback from the computer may prompt him to seek help.

Comments: Text in italics
Interviewer: Text in red
Brad: Text other colour

Interviewer:
In this game you have to type a number which fits on the numberline.

Interviewer:
You can see the two endpoints on the screen

Brad:
A half is between nothing and one, so, 5 tenths...point 5

Interviewer:
Good. The computer has accepted your answer

Interviewer:
...and changed the numberline for your next turn.

Brad:
Now nothing to five tenths...I'll try 3 tenths

Computer accepts 0.3 and presents a new numberline.

Interviewer:
OK. Now try to get between point 3 and point 5.

Brad:
Easy, point 4.

Interviewer:
OK, what about between point 4 and point 5?

Brad:
But there is no number between point 4 and point 5! (long pause)

Interviewer:
Do you want to try something like point four five?

Brad:
That won't fit because it's far too big! Point four five is 45 tenths and it's a lot bigger than 5 tenths.

Brad tries 0.45 as suggested and is surprised that it is accepted.

Brad:
But that doesn't make sense because 45 tenths is bigger than 5 tenths??!!