# Adding and Subtracting Fractions

We've always found that the easiest way to understand adding and subtracting fractions is by seeing 👀 fractions in action.Pick whichever you vibe with more:

INTRO

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Think of a fraction like this:

The

denominator

, $4$

, tells us the size of the slice. The numerator

, $1$

, tells us how many slices we have of that size.CALCULATOR

—

## Adding & Subtracting Fractions Calculator

### Use the LCM

KEY STEPS

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## How to Add & Subtract Fractions

### Use the LCM

### Step 1. Check the denominators. If they match, skip to Step 4.

### Step 2. Multiply the numerator and denominator of fraction 1 by the denominator of fraction 2.

### Step 3. Multiply the numerator and denominator of fraction 2 by the denominator of fraction 1 from the original equation.

### Step 4. Add/subtract the numerators, and keep the denominator the same.

LESSON

— Multiplying by the Denominators

## Multiplying by the Denominators

A reliable way to find the common denominator is to multiply the two denominators together.

But, when we do this, we have to make sure we multiply both the top and bottom by the same thing. Look what happens if we only multiply the denominators:

Original | $42 $ | $+$ | $51 $ |

Multiply by Denominator | $42 ×5×5 $ | $+$ | $51 ×4×4 $ |

New | $202 $ | $+$ | $201 $ |

Y’all see what we see?! 👀 What happened to all our pizza?! When we only multiply the denominators, the amount of pizza changes, and we end up solving an entirely different problem.

PRACTICE

— Multiplying by the Denominators

## Practice: Multiplying Denominators

Question 1 of 3: $52 +31 =?$

### Step 1. Check the denominators to see if they're the same.

Are the denominators the same?

LESSON

— Using the LCM

## Using the LCM

We can also find a common denominator by finding the LCM, or least common multiple, of the two denominators.

### Is Using the LCM Better than Multiplying by the Denominators? 🤔

Tbh… it depends on what comes more naturally to you. 🤷🏻

Both methods will always get you to the correct answer, but you may end up having to deal with larger numbers when multiplying by the denominators.

In addition, using the LCM can come in pretty handy when solving problems that involve more than two fractions.

PRACTICE

— Using the LCM

## Practice: Using the LCM

Question 1 of 3: $92 +61 =?$

### Step 1. Check the denominators to see if they're the same.

Are the denominators the same?

CONCLUSION

—

Sheesh, look at you go! Thanks for checking out this lesson ☺️🙏.

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