An integer is a number that does not have fractions or decimals. Examples of integers are 50, - 1. A fraction is a number that is made up of numerators and denominators. An example is 3/4. A decimal is made up of tenths, hundredths and thousandths. An example is 2.3.
Negative three-fourths is not an integer because it is a fraction. 2.3 and pi is not an integer because it is a decimal.