All numbers can be written as fractions.  All whole numbers would be written in the following way:

4 = 4
       1

Any number over itself is an expression of the number 1

Fractions indicate division.  1/2 is one divided by two.  1/3 is one divided three ways.
If we actually do that division, we can turn a fraction into a decimal.

1 / 3 = 0.333 (repeating)
1 / 10 = 0.1

You can use long division (or a calculator) to get this result.

Some fractions allow you to take short cuts.  Example:

 40
200     We can divide any number (including fractions) by one and get the same number

In this case we might decide to divide this fraction by   2
                                                                                                  2   which will not change the value because it's 1

we end up with  20
                            100  which is literally 20 hundredths.  This number is 0.20 in decimal form.

See place value

Percents are the decimal representation for a fraction multiplied by 100.  Just slide the decimal over to the right two places!

0.47 = 47%
1.2 = 120%
0.012 = 1.2%