Question

How many number of zeros are there between 0 and 10000?

Answer 1

10 20 30 40 50 60 70 80 90=no of zero=9
means b4 100 total no of zero=9
110 120 130 140 150 160 170 180 190 =no of zero=9
means after 100 and before 200 no zero=9
similarly ..no of zero between 200 and 300 =9
and so on...
no of zeros between 900 and 1000=9
and some zeros at 100 200 300........900
so total no of zero before 1000=10*9+9*2=12*9=108
means before 1000 no of zeros=108 so before 2000=108
similarly....
..............
before 10000 no of zeros=108
and some at 1000 2000 3000 .......9000 and one 10000
so total no of zeros became=108*9+9*3+4=972+27+4=1003
1003 is the ans