Mammoth Memory

Decimal to fraction - Repeating

If you have a repeating decimal it is the division of any number by `9` that makes it repeat.

i.e.   `1div9=1/9=0.111dot1`

`2div9=2/9=0.222dot2`

`3div9=3/9=0.333dot3`

Repeating decimals are the result  of a division including 9 

I keep seeing nines everywhere doctor.

 

For repeating decimals think

  `0` `*` `1` `1` `1` `1` `1` etc
      `darr` `darr` `darr` `darr` `darr`  
     

`1/9`

`1/90`

`1/900`

`1/9000`

`1/(90,000)`

 

Or

  `0` `*` `2` `2` `2` `2` `2` etc
      `darr` `darr` `darr` `darr` `darr`  
      `2/9` `2/90` `2/900` `2/9000` `2/(90,000)`  

Or

  `0` `*` `3` `3` `3` `3` `3` etc
      `darr` `darr` `darr` `darr` `darr`  
      `3/9` `3/90` `3/900` `3/9000` `3/(90,000)`  

 

 Find where it starts repeating and the number it repeats



Example 1

Convert `0.dot2` to a fraction

`0.dot2=0.222222` recurring.

Remember:

`0` `*` `2` `2` `2` `2`
    `darr`      
    `2/9`      

Therefore

`0.dot2=2/9`

Now check on a calculator `2div9=0.22dot2`

 

Example 2

Convert `0.0dot2` to a fraction

`0.0dot2=0.0222222` recurring.

Remember:

`0` `*` `2` `2`
    `darr` `darr`
    `2/9` `2/90`

Therefore

`0.0dot2=2/90=1/45`

Now check on a calculator `2div90=0.022dot2`

 

Example 3

Convert `0.000222dot2` to a fraction

`0.000dot2=0.000222222` recurring.

Remember:

`0` `*` `2` `2` `2` `2`
    `darr` `darr` `darr` `darr`
    `2/9` `2/90` `2/900` `2/(9,000)`

Therefore

`0.dot2=2/(9,000)=1/(4,500)`

Now check on a calculator `2div9,000=0.00022dot2`

 

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