The task is to generate the correct answer for a given math problem.

[Q]: Problem: if 1.5 cm of a pencil is purple , 0.5 cm of the remaining is black and the remaining 2 cm is blue , what is the total length of the pencil ?
[A]: 4 cm


[Q]: Problem: how many numbers between 400 and 1000 can be made with the digits 2 , 3,4 , 5,6 and 0 ?
[A]: 60


[Q]: Problem: how many figures are required to number the pages the pages of a book containing 2200 pages ?
[A]:
7693