Multi-Step Equations With Fractions

Contributor: Ashley Nail Murphy. Lesson ID: 14182

Ready for an adventure? Every adventure needs snacks! Use multi-step equations with fractional coefficients to help you sharpen your problem-solving skills...and make snacks!

categories

Arithmetic, Elementary

subject
Math
learning style
Kinesthetic, Visual
personality style
Lion, Otter, Beaver, Golden Retriever
Grade Level
Intermediate (3-5)
Lesson Type
Quick Query

Lesson Plan - Get It!

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Alex and Jade are getting ready for a camping adventure and decide to mix up a big bowl of trail mix for a snack.

Alex brought raisins, and Jade brought peanuts. They combine the ingredients in a large bowl and stir them up!

bowl of mixed nuts and raisins

Alex adds 4 cups of raisins to the mix. Jade brought a lot of peanuts, so they decided only to use 2/3 of her peanuts.

After mixing, they end up with 10 cups of trail mix.

Now, here’s the challenge.

  • How many peanuts did Jade bring?

To solve this, Alex's dad writes an equation.

  2 p + 4 = 10
  3

 

In this equation, p stands for the amount of peanuts Jade brought.

The friends used 2/3 p cups of Jade’s peanuts plus 4 cups of Alex’s raisins to make 10 cups of trail mix in total.

Use what you know about fractions and solving equations to help the campers!

Look at the equation.

  2 p + 4 = 10
  3

 

  • What do you notice?
  • Any ideas?

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  • How many of those things did you notice?

Look at the parts of this equation.

equation

p is a variable. A variable is a symbol for an unknown value. You need to find the value of p in this equation — the number of peanuts Jade brought.

2/3 is the coefficient. A coefficient is a number that is multiplied by the variable. This number is always right before the variable.

  So, 2 p means 2 x p.
  3 3

 

Now that you understand the important parts of this equation, you can start to solve it!

Step 1: Isolate p

First, you need to get rid of the + 4 so that you can focus on p.

Since it says + 4, do the opposite. Subtract 4 from both sides of the equation.

This step brings you one step closer to isolating p.

Look closer at the first step.

  2 p + 4 - 4 = 10 - 4
  3

 

  • What are you left with?
  2 p = 6    
  3

 

Step 2: Remove the Coefficient

Now, you are ready to isolate the p by getting rid of 2/3.

Remember, since 2/3 is a coefficient, you are multiplying it by p. To reverse that, do the opposite operation, which is division.

  2 p ÷ 2 = 6 ÷ 2
  3 3 3

 

This is where it gets tricky! In order to divide fractions, you need to multiply using a reciprocal. A reciprocal is when you flip a fraction.

  So, 2 becomes 3 .  
  3 2

 

Remember this phrase: Keep. Change. Flip. Keep the first number, change the division to multiplication, and flip the second fraction.

Apply this to both sides of the equation.

  So, 2 p ÷ 2 = 6 ÷ 2 becomes 2 p x 3 = 6 x 3
  3 3 1 3 3 2 1 2

 

  2 p x 3 = 0 p
  3 2

 

  6 x 3 = 18
  1 2 2

 

Step 3: Solve and Simplify

Now, p is alone, and you solved the equation! All you have to do is simplify.

  p = 18 = 18 ÷ 2 = 9
  2

 

p = 9

p was the unknown amount of peanuts Jade brought camping. Jade had 9 cups of peanuts before they made trail mix! That was a lot of peanuts!

Check out the images below to review the steps to solve this equation in order.

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This skill not only helps you solve equations but also builds your problem-solving abilities, preparing you for future mathematical adventures.

Visit the Got It? section to practice!

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