Question

How many times does the digit 9 occur between 1 and 100? write the number

Answer 1

AnSwer:

★1st Case ( natural numbers ):-

If we consider all the natural numbers between 1 to 100 then 9 will occur 20 times,

Series:

• 9,19,29,39,49,59,69,79,89,99(10 times in unit digit)

• 90,91,92,93,94,95,96,97,98,99(10 times ten's digit)

So there are 20 nine's occuring between 1 to 100.

★2nd Case ( real numbers ):-

If we consider all the real numbers between 1 to 100 then 9 will occur infinite number of times,

There will be 20 numbers of the earlier ones(natural numbers), as well as, there will be decimals like 2.39, 4.59, and many more.

So, it may occur infinite number of times.