How do you convert........ without a calculator?

Question

How do you convert (without a calculator):

1.Fractions to Decimals - eg 3/20 as a decimal

2.Fractions to Percentages eg 3/40 as a percentage

3.Decimals to Fractions (is it the same as Fractions to Decimals?)

4.Percentages to Fractions (is it the same as Fractions to Percentages?)

Please show working out! Thanks.

Answer 1

Isn't that what schools for..

Answer 2

This is how I learnt it ages ago.

1.) You start off like this:

3:20=

Then, because 3 is smaller than 20 you add a 0 to the 3 and to the result so it becomes this:

30:20=0.

Then you devide it.

        30:20=0.1

       -20

______

       10

Now you do the same thing with the 10. You add a 0.

So your written result will now look like this:

       30:20=0.15

       -20

_______

       10O : 5 = 5

       -100

______

          0

And thats the end result!!! Easy really!

And you do it that way with all the other equations.

Hope this way is easier for you?

Fractions to percentages is similar.

2.) 3:40=

becomes

300:40=0.0

becomes

300:40=0.07

-280

_____

20

becomes

300:40=0.075

-280

_____

20O:40=5

-200

____

0

3.) Decimals into fractions, e.g. 0.25 into a percentage works like this: (not the same as 1.!)

100% is your highest percentage.

So you multiply 100 times 0.25 and it gives you 25%. And thats the result!

4.) Percentages to fractions, e.g. 50% works like this:

50:100 = 1/2

You look for the number both numbers can be devided by and factorize it. In this case it's 50. (I think its called the common denominator perhaps?)

And its the OPPOSITE way round to 3.)!

Best of luck and don't give up! xx

Answer 3

Fractions to decimals-

To turn fractions to decimals we divide the numerator by the denominator.

3/20 as a decimal is 3 divided by 20 = 0.15

3 cannot be divided by 20 so we make it 30 divided by 20 = 1.5. Since we ‘borrowed’ or added 10 to one side of the equation making the three 30, we must remove it from the answer by moving the decimal point => 1.5 becomes 0.15

Fractions to percentages-

To turn fractions to decimals we divide the numerator by the denominator to give us a decimal figure, and then multiply by 100.

Since, from the previous calculation we know that 3/20 is 0.15 to return 3 as a percentage of 20; we multiply the 0.15 by 100 = 15%.

Or, we take the denominator, the bottom part of a fraction and make it 100, so 20*5=100. We must do the same to the numerator, the top of the fraction. Thus 3 becomes 3*5= 15 which is the percentage.

Decimals to fractions-

0.15

Multiply by 100 (because there are 2 digits after the decimal place):

0.15 * 100 = 15

Then



1 * 100 = 100 so we have 15/100

Then simplify the fraction, if necessary- 15/5 = 3 and 100/5 = 20 so we have 3/20.

Fractions to percentages-

15% expressed as a decimal is 0.15 we know. The decimal 0.15 expressed as a fraction is 1 tenth and 5 hundredths. (Or 1/10 and 5/100)

So, we need to find a common denominator. Since one tenth is 10/100 we can add the two. 10/100 + 5/100 = 15/100. Again, we reduce the fraction to its lowest denominator thus-

15 divided by 5 = 3. 100 divided by 5 = 20 giving us 3/20.

I hope this is clear. If not, I've added a couple of links, but 'google' and there are a plethora of sites dedicated to the subject.

Answer 4

1) change the denominator to 100, so

3/20 = 15/100 = .15

2) change denominator to 100 first, so

3/40 = 7.5/100 =  .075

change decimal to percent, multiply by 100, so

.075 *100 = 7.5%

3) yea convert decimal to a fraction with denominator 10 or 100 and then simplify

.2 = 2/10 = 1/5

4) 5% = 5/100 = 1/20 same concept

Answer 5

Okay so:

Fractions to decimals=

Eg: 3/20 > decimals

All you need to do is actually divide them so 3/20 becomes 3 divided by 20 and ta da theres your decimal.

Fractions to percentages=

Eg: 3/40 > percentage

All you do for this one is change it to a decimal first so its 3/40 becomes 3 divided by 40. Then times the decimal by 100 and put a % sign after it and its a percentage!

Decimals to Fractions=

Well for this one its NOT the same you have to remember a few simple convertions and work out the rest from them. Learn these:

0.1= 1/10                              

0.15 = 15/100

0.2 = 2/10                      

0.32 = 32/100

0.3= 3/10                      

0.06= 6/100

Etc

Percentages to Fractions=

Well divide your percentage by 100 and you'll have changed it to a decimal and then change that to a percentage using the stuff above. ^^

Answer 6

3.00 / 20 =0.15

3.00 / 40 = .075

0.15 * 100 = 15%

0.075 * 100 = 7.5 %

and so on