var index=Math.round(Math.random()*(3-1))+1; var fraction=new Array(4); var truevalue=new Array(4); fraction[0]='
1
109
'; truevalue[0]='0.000000001'; fraction[1]='
1
109
'; truevalue[1]='0.000000001'; fraction[2]='
1
105
'; truevalue[2]='0.00001'; fraction[3]='
1
107
'; truevalue[3]='0.0000001'; window.document.write('

Decimals



Decimals are frequently more convenient to work with than fractions. They are also found more commonly in chemistry. The decimal places are frequently given names indicating their magnitude. Here´s an example.

If you wish to read out the value of a small decimal number, read the decimal number and then its value. For example, 0.4928 written as a fraction would be:

4928
10000

This would be read as four thousand nine hundred twenty-eight ten-thousandths.

In order to change a fraction into decimal form, divide the numerator by the denominator. Here are a few examples.

3   9   4   1   346  
=0.75 
=1.8 
=0.8 
=0.333 
=0.484
4   5   5   3   715  

In the first three examples, the division terminates. In the last two examples, further digits are obtained on the calculator. How do you know to drop these additional digits? The answer to this is found in the section on significant figures and rounding off calculations.

Many of the units of the Metric System are defined as fractions consisting of one divided by multiples of ten. In order to convert these fractions to decimals, write a one, and then move the decimal point to the right the number of decimal places indicated by the exponent of the denominator. Here are a few examples.

1   1   1   1  
=0.1 
=0.01 
=0.001 
=0.000001
101   102   103   106  

Convert the following fraction to decimals.

' + fraction[index] + '
'); var index2=Math.round(Math.random()*(6-1))+1; var equation=new Array(7); var truevalue2=new Array(7); equation[0]='

0.891 x 105

'; truevalue2[0]='89,100'; equation[1]='

0.891 x 105

'; truevalue2[1]='89,100'; equation[2]='
75.9
104
'; truevalue2[2]='0.00759'; equation[3]='

67.3 x 103

'; truevalue2[3]='67,300'; equation[4]='
75,600
105
'; truevalue2[4]='0.756'; equation[5]='

0.0000583 x 106

'; truevalue2[5]='58.3'; equation[6]='
64.9
103
'; truevalue2[6]='0.0649'; window.document.write('

In the Metric System, you will frequently multiply and divide decimal numbers by powers of ten. This can be done on a calculator, but it is also possible to carry out the math just by inspection. Here´s how.

 1. When multiplying by powers of ten, move the decimal point to the right by the number of places indicated by the exponent.
2. When dividing by powers of ten, move the decimal point to the left by the number of places indicated by the exponent.		 

Here are a few examples.

0.00482 x 103 = 4.82decimal point moved three places to the right
3.83 x 105 = 383,000decimal point moved five places to the right
15.9  
=0.00159
104  
decimal point moved four places to the left
0.000862  
=0.000000862
103  
decimal point moved three places to the left

Try another example. Convert the following expression to a simple decimal format.

' + equation[index2] + '
');