The general evaluation is the knowledge learned in the second volume of fifth-grade mathematics by People's Education Press. It is an important basis for learning the comparison of fractions with different denominators and the addition and subtraction of different denominators. Therefore, the general evaluation must be the knowledge that every student must master.

According to the basic properties of fractions (formulas), simplifying fractions into a common denominator is a process of converting several fractions (formulas) with different denominators into fractions (formulas) with the same denominator, which is called general fractions.

The key to general division is to determine the simplest common denominator of several fractions, and the steps are as follows:

1. List denominators respectively.

2. Multiply the denominator divisor. If there is a common divisor, the result is the least common multiple of the denominator.

3. All the letters or factors based on letters should be taken.

4. The factor with the same letter or the power of the factor with the letter takes the largest exponent.

5. Multiply all the above formulas to get the simplest common denominator.