Subtracting Mixed Numbers Unlike Denominators – with Video Tutorials that Make Sense

Subtracting Mixed Numbers with Unlike Denominators

Subtracting Mixed Numbered Fractions like 3 ½ – 2 ¾ can be very confusing for children.  First, they have to find common denominators.  Next, they have to borrow from the whole number and change it into a fraction.  Finally, they subtract.  If children only learn the algorithm, then they have a very difficult time understanding what is really happening with the subtraction of mixed numbered fractions.

In this seventh Video-Post, I will demonstrate how to subtract mixed numbered fractions that have unlike denominators.  If you are new to these Video-Posts, I encourage you to start with the first video-post, because each post builds upon what was taught in the last.

Seven-Video-Posts

  1. An Introduction to Illustrating Fractions
  2. Adding Fractions with Common Denominators
  3. Subtracting Fractions with Common Denominators
  4. Adding Fractions with Unlike Denominators
  5. Subtracting Fractions with Unlike Denominators
  6. Adding Mixed Numbered Fractions
  7. Subtracting Mixed Numbered Fractions

 

How to use these Video-Posts

These Video-Post are designed in a similar manner to how I teach a concept in my class.

  • First, children will be introduced to a concept with a “WATCH ME” demonstrational video.
  • Next, children continue developing their skills by working side-by-side with me. They are given a problem and work through that problem, while they watch the “WORK WITH ME” video.
  • Finally, children perfect their skills by completing problems by themselves. Then they will watch the “ON YOUR OWN” videos.  These last videos encourage the child’s independent work, and then review the problem making sure that the child gains understanding.

Sloth

6.1- Watch Me
You are on vacation in the rain forest of South America.  You discover a slow sloth clawing across the ground.  He is headed for a large tree 3 & 3/4 yards away.  You watch his slow progress as he moves one foot in front of the other.  After a full minute the slow sloth has only traveled 2 & 5/6 yards.

How much further does your slow moving sloth have to travel before he reaches his tree?

Your Challenge:
This one is easy.  Watch the video below to see how to add these fractions.  Pay close attention.  Your next challenge will be very similar to this one.

Hungry Octopus

6.2 – Work with Me
You are part of the Junior Marine Biology Club of America.  Your Club is scuba diving off the coast of Monterey California.  You observe an octopus eating clams.  There are 2 & 2/3 hidden in the sand.  The octopus finds and eats 1 & 4/5 of the clams.

How many clams does the octopus have left to eat?

Your Challenge:
This one is a little harder.
Gather the following materials:

  • A blank piece of paper
  • A pencil
  • A Sharpie marker
  • Crayons
  • A highlighter

Watch and complete this challenge with me.  I will take you through a step-by-step process.  Together, we will solve this problem.

Pay close attention.  Your next challenge will be very similar to this one.

Carrot Chomping Horse

6.3 – On Your Own
You have wanted a horse of your own for as long as you can remember.  You have saved and saved.  Finally, you have enough money for your horse.  She is a beautiful mare and she loves chomping on carrots.  You buy 2 & 7/9 carrots for her.  She chomps away 1 & 2/3 of the carrots.

How many carrots are left?

Your Challenge:
Gather the following materials:

  • A blank piece of paper
  • A pencil
  • A Sharpie marker
  • Crayons
  • A highlighter
  • A blank piece of paper

Complete the illustration and the algorithm to find the answer to this problem.

Don’t worry if you make a mistake – Some of our biggest leaps in learning come when we make a mistake then see what we did wrong and fix it.

Once you have completed this challenge, click the play button on the video below:

Keep your paper with you while you watch the video.
If you make a mistake, pause the video and fix your mistake.
That’s the fastest way to learn!

 

Snowy Owl

6.4 – On Your Own
A beautiful snowy owl has moved into a tree behind your house.  She has three baby owls that recently hatched and are growing fast.  The mother owl has killed 3 & 1/2 mice.  Her baby owls eat 2 & 5/8 of the mice.

How many more mice do the baby owls have to eat?

ur Challenge:
Gather the following materials:

  • A blank piece of paper
  • A pencil
  • A Sharpie marker
  • Crayons
  • A highlighter
  • A blank piece of paper

Complete the illustration and the algorithm to find the answer to this problem.

Don’t worry if you make a mistake – Some of our biggest leaps in learning come when we make a mistake then see what we did wrong and fix it.

Once you have completed this challenge, click the play button on the video below:

Keep your paper with you while you watch the video.
If you make a mistake, pause the video and fix your mistake.
That’s the fastest way to learn!

Burger Eating Panda

6.5 – On Your Own
You just made friends with a red panda.  He is totally cute, but a little messy.  His favorite food is hamburger.  You take him to In & Out Burger and order 2 & 2/3 burgers.  He eats 1 & 5/7 burger in about 8-seconds.

How many burgers does your red panda buddy have left to eat?

Your Challenge:
Gather the following materials:

  • A blank piece of paper
  • A pencil
  • A Sharpie marker
  • Crayons
  • A highlighter
  • A blank piece of paper

Complete the illustration and the algorithm to find the answer to this problem.

Don’t worry if you make a mistake – Some of our biggest leaps in learning come when we make a mistake then see what we did wrong and fix it.

Once you have completed this challenge, click the play button on the video below:

Keep your paper with you while you watch the video.
If you make a mistake, pause the video and fix your mistake.
That’s the fastest way to learn!

Want more Tutorials?

I’ve created an Educational Fantasy Game called, TeachersDungeon.  It is set to the Common Core Educational Standards, and is web-based, so it can be played on any device.  Many of the questions are accompanied by tutorials like the ones you saw here.

Novels by Brian McCoy

My Adventures with ChickenSpike – A Children’s Fantasy Book intended for readers in 2nd through 4th

 

 

RED – an Action & Adventure Novel intended for readers in Middle School

 

 

 

Let me know if there is any way I can help!
Until next time…
Have a great day – Brian McCoy

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