Please help.. Just a quick one

How many times of digit '5' from 1 to 1 000 000? feel free to suggest any method available in math knowledge

Question

Please help.. Just a quick one

How many times of digit '5' from 1 to 1 000 000? feel free to suggest any method available in math knowledge

anonymous · Answer

first of all count 5's that come in unit place then count 5's that come in digit place and so on i know it is quity lengthy process and u'll hav to omit the no in which 5 comes more than on time

yttrium · Answer

Let's consider the number from 1-100000 like this:
1. 0 000 001
2. 0 000 002
3. 0 000 003
.
.
.
1 000 000. 1 000 000 000

yttrium · Answer

As you see, we use 7 digits to represent each numbers. All in all, we use 7*1,000,000 = 7,000,000 digits. Right?

yttrium · Answer

As we all know, we use 10 numbers from (0-9) to represent new number. Hence, from (0-9) we have equal distribution of digits. 7,000,000/10 = 700,000 digits

anonymous · Answer

thank you guys. for me, im using the probabilities of digit 5 in 10, then 100 and so on untill 1 000 000. And my answer would be 460k++... but im not sure whether it would be the best way to solve correctly or not.

anonymous · Answer

@Yttrium but how do you calculate digit 5 in 500,5k,50k,500k?

terenzreignz · Answer

Just to be clear... it's 'how many times the digit "5" appears in all the integers from 1 to 1000000' ?

anonymous · Answer

@terenzreignz yup. thank you for asking

terenzreignz · Answer

Well then, first count the number of multiples of 5.

terenzreignz · Answer

Easily, there should be 200000.

terenzreignz · Answer

wait wrong reasoning... whoopsie

anonymous · Answer

@terenzreignz same with me here!! is it right? i got around 460k or to be exact 468559times digit '5' appeared in a million.

ganeshie8 · Answer

permutations kicks in

anonymous · Answer

@ganeshie8 i used that!! 460k would be the right answer i suppose?

ganeshie8 · Answer

clos, 468559

ganeshie8 · Answer

*close

anonymous · Answer

thanks! @ganeshie8 @terenzreignz

ganeshie8 · Answer

np :) here is the working, hope u did more/less the same way http://www.wolframalpha.com/input/?i=6*9%5E5+%2B+%286+choose+2%29*9%5E4+%2B+%286+choose+3%29*9%5E3+%2B+%286+choose+4%29*9%5E2+%2B++%286+choose+5%29*9%5E1+++%2B++%286+choose+6%29*9%5E0

anonymous · Answer

@ganeshie8 yess!! thanks alot!

ganeshie8 · Answer

cool yu wlcme!!