Scientific calculators

[AngloScot]

How do you enter a recurring decimal? My calculator is a casio fx-83WA S-V.P.A.M.

[georgeous]

Hey to add a rcurring decimal either type in the fraction and it will come out as recurring such as 1 / 3. Or if this is confusing you can just type for example 0.333333333333 until it goes over 10 so that it counts as recurring, although im not totally sure this is 100% accurate. Also, you could use the memory button to add a recuring decimal to it and them recall it when you need to.

[NetSquirrel]

I do what georgeous has said - simply divide two numbers so that the result has a recurring decimal.  You have almost the same model of calculator as I do so I don't think there is a better way than this (but what could be quicker anyway?)

 

All the recurring decimals where it is all the same number (0.1111111..., 0.2222222... etc.) are just x/9.  So 1/9 = 0.1111111...; 5/9 = 0.5555555... and so on.

 

For the more difficult ones, such as 0.7171717171... you can work them out like this:

 

x = 0.7171717171...

100x = 71.7171717171...

100x - x = 99x

71.7171... - 0.7171... = 71

99x = 71

x = 71/99 = 0.7171717171...

 

You can see that, for single recurring decimals (0.xxxxxxxxx...) you divide "x" by 9 to get the decimal on the calculator.  For double recurring decimals (0.xyxyxyxyxy...) you divide the number "xy" by 99 where xy is not "x times y" but a number, e.g. for 25, x = 2, y = 5.  For a three-number recurring decimal, you divide "xyz" by 999 and so on, so you see you can quickly get this kind of number on your calculator screen.

 

For recurring decimals that do not recur from the start, e.g. 0.596424242424242... you can either add 0.596 to the easy fraction 0.424242... (but divided by 1000) or work them out in a single fraction, i.e. 59,046 / 99,000 = 0.596424242...