# Why can you not add fractions with unlike denominators?

## Why can you not add fractions with unlike denominators?

When adding fractions, why don’t you add the denominators? A denominator indicates how many equal pieces make one unit. If you add the denominators when adding fractions, the new denominator won’t describe how many equal pieces are in one unit.

Why do the denominators have to be the same when adding fractions?

If you’re adding two fractions with a common denominator, you can combine them together by adding the numerators together (the top numbers). The denominator will always stay the same because the size of the equal pieces does not change when you combine the two fractions together.

### Can you add and subtract fractions with unlike denominators?

Steps How to Add or Subtract Fractions with Different Denominators. Step 1: Given two unlike fractions where the denominators are NOT the same. Step 2: Make the denominators the same by finding the Least Common Multiple (LCM) of their denominators. Step 4: Now, add or subtract the “new” fractions from step #3.

How do you add fractions with unlike denominators?

1. Find the LCM of the two denominators. Suppose you want to add the fractions 3/4 + 7/10.
2. Increase the terms of each fraction so that the denominator of each equals the LCM.
3. Substitute these two new fractions for the original ones and add.

## What is the least common denominator of 7/10 and 3 5?

210
Calculate the LCM The least common multiple of 3, 5, 7 and 10 is 210.

Can you cancel out when adding fractions?

1 Expert Answer It only works for division and multiplication. To add and subtract, you have to get a common denominator. Then you can add or subtract the numerators and keep the denominator.

### How do you add and subtract fractions with unlike denominators and whole numbers?

Step 1: Find the Lowest Common Multiple (LCM) between the denominators. Step 2: Multiply the numerator and denominator of each fraction by a number so that they have the LCM as their new denominator. Step 3: Add or subtract the numerators and keep the denominator the same.

How do you add mixed numbers with different denominators?