# 13/20 - 157/41 = ? Subtracting Ordinary (Simple, Common) Math Fractions Calculator, Subtraction Explained in Detail

## Add ordinary fractions, online calculator

 20/75 - 25/14 = ? May 09 11:52 UTC (GMT) 13/20 - 157/41 = ? May 09 11:52 UTC (GMT) 23/86 - 929/152,408 = ? May 09 11:52 UTC (GMT) 27/39 - 20/46 = ? May 09 11:52 UTC (GMT) - 25/138 - 36/19 = ? May 09 11:52 UTC (GMT) 19/72 - 11/589 + 86/24 + 27/106 = ? May 09 11:52 UTC (GMT) 588/103 + 33/12 = ? May 09 11:52 UTC (GMT) 7/112,338 + 3 = ? May 09 11:52 UTC (GMT) 25/5 - 16/15 - 132/10 = ? May 09 11:52 UTC (GMT) 629/123 + 49/130 = ? May 09 11:52 UTC (GMT) - 23/59 - 27/12 = ? May 09 11:52 UTC (GMT) 41/22 + 9/25 = ? May 09 11:52 UTC (GMT) - 28/86 + 42/951,849 = ? May 09 11:51 UTC (GMT) see more... added fractions

## How to: Adding ordinary (simple, common) math fractions. Steps.

There are two cases regarding the denominators when we add ordinary fractions:

• A. the fractions have like denominators;
• B. the fractions have unlike denominators.

### A. How to add ordinary fractions that have like denominators?

• Simply add the numerators of the fractions.
• The denominator of the resulting fraction will be the common denominator of the fractions.
• Reduce the resulting fraction.

### An example of adding ordinary fractions that have like denominators, with explanations

• #### 3/18 + 4/18 + 5/18 = (3 + 4 + 5)/18 = 12/18;

• We simply added the numerators of the fractions: 3 + 4 + 5 = 12;
• The denominator of the resulting fraction is: 18;

### B. To add fractions with different denominators (unlike denominators), build up the fractions to the same denominator. How is it done?

• #### 1. Reduce the fractions to the lowest terms (simplifying).

• Factor the numerator and the denominator of each fraction down to prime factors (prime factorization).
• #### Factor numbers online down to their prime factors.

• Calculate GCF, the greatest common factor (also called GCD, greatest common divisor, HCF, greatest common factor) of each fraction's numerator and denominator.
• GCF is the product of all the unique common prime factors of the numerator and the denominator, taken by the lowest exponents.
• #### Calculate online the greatest common factor, GCF.

• Divide the numerator and the denominator of each fraction by their greatest common factor, GCF - after this operation the fraction is reduced to its lowest terms equivalent.

• #### 2. Calculate the least common multiple, LCM, of all the fractions' new denominators:

• LCM is going to be the common denominator of the added fractions.
• Factor all the new denominators of the reduced fractions (run the prime factorization).
• The least common multiple, LCM, is the product of all the unique prime factors of the denominators, taken by the largest exponents.

• #### 3. Calculate each fraction's expanding number:

• The expanding number is the non-zero number that will be used to multiply both the numerator and the denominator of each fraction, in order to build all the fractions up to the same common denominator.
• Divide the least common multiple, LCM, calculated above, by each fraction's denominator, in order to calculate each fraction's expanding number.
• #### 4. Expand each fraction:

• Multiply each fraction's both numerator and denominator by expanding number.
• At this point, fractions are built up to the same denominator.
• #### 5. Add the fractions:

• In order to add all the fractions simply add all the fractions' numerators.
• The end fraction will have as a denominator the least common multiple, LCM, calculated above.