In algebra, students use letters and symbols in place of numbers in order to solve mathematical equations. In this branch of math, the term "integer" is frequently used. An integer is any whole number, whether that number is positive or negative. Fractions are not whole numbers and, thus, are not integers. Integers come in multiple forms and are applied in algebraic problems and equations.

### Positive Integers

Commonly, integers come in the form of a positive whole number. This means that any number in the following set (1, 2, 3, 4...) is a positive integer. The three dots signify a continuing chain of integers after four. Numbers such as 1.25, 4.003 and Pi are positive numbers, but because they are not whole, they are not integers.

### Negative Integers

Integers can also be negative whole numbers. Any number in this set (...-4, -3, -2, -1) is a negative integer. Similar to positive integers, numbers such as -3.5 and -10 are not integers because they are not whole.

### Zero

Another way to look at integers is to say that an integer must be even or odd. Using this logic, zero is an integer, as it is an even whole number. Zero is not classified as a positive or negative number or integer.

### Algebra Word Problems

In algebra, you may be asked to solve an equation by providing the missing integer. For example, a word problem may say that the sum of two consecutive integers is 29. What are the integers? To solve, set up an algebraic equation -- X + (X+1) = 29 -- and solve for X. This simplifies to 2X + 1 = 29 and then 2X = 28. This means that X = 14 and the two consecutive integers in question are 14 and 15.