Step by step
The question
Question: What is the 20th digit after the decimal point of 5/11?
1 Find the block
50 divided by 11 is 4, and 6 is left.
We divide 5 by 11 the long way.
Each time we bring down a 0.
60 divided by 11 is 5, and 5 is left.
5 left: that is where we started.
So the digits repeat from here.
So 5/11 is 0 point 4 5, and the same 2 digits again and again.
The block is 2 long.
2 Divide
The block comes again and again.
So we divide by its length.
What is left over tells us the place in the block.
2 times 10 is 20.
So 10 full blocks take us to the 20th digit.
20 minus 20 is 0 more.
3 Count into the block
Nothing is left over.
So the 20th is the end of a block: the last one, 5.
4 Check
Let's check by counting on.
A block ends at the 18th digit.
Then we count on: 4, 5.
The 20th is 5.
So it is right!
Let's look back.
First: find the block.
Then: divide.
Then: count into the block.
Last: check.