Read the following article and answer the question.

The rest was not bad at all , although I thought I was going to get a 21 + on this section , so I must have been over confident . QR : This section obviously killed me , not because it was hard at all , but because it was fast . It seemed that all my problems involved long division to get decimals and took 2 min plus a problem .

Why do I feel I was overconfident on this section ?
I thought I would score more points but I ran out of time and did n't do well .