Introduction
Brad can make the largest and smallest numbers with two decimal places, but for the wrong reasons. His reasoning reveals that he has little understanding of place value.

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

Interviewer:
I have a number that starts 3 point something something and you get to choose the rest of the number.

Interviewer:
Here are the cards to choose from...

Interviewer:
... marked 0,1,2,3,4,5,6,7,8 and 9. I'm going to ask you to make the biggest number that you can by choosing any two of these cards.

Brad chooses the 9 and the 8

Brad:
98 is the biggest number

Interviewer:
OK, now we'll put those cards back

Interviewer:
...and could you make another number, this time as small as you can?

Brad makes 3.01

Interviewer:
OK, and what were you thinking?

Brad:
Well the zero at the start makes it small.

Brad knows that 0.01 is one hundredth, which is smaller than any other number of hundredths or tenths.