Slice and Dice Slides Chef Crumb's Monster Diner
Grade 5 Math • Day 1
Warning: Delicious Math Ahead!
Slice & Dice:
Multiplying Fractions
Discover why multiplying fractions makes things smaller and master the visual grid smash!
Today's Goal: Multiply fractions using visual models & the algorithm
Slide 1 of 8
WARM-UP
Spiral Kitchen Prep (3 Minutes)
Fast Mental Math!
#1 Add Like Terms
Find common denominators and solve:
\(\frac{1}{2} + \frac{1}{4} = ?\)
Hint: Half a pizza + quarter pizza
#2 Simplify!
Reduce to the simplest lowest terms:
\(\frac{6}{8} = ?\)
Hint: Divide top & bottom by 2
#3 Pie Mystery
Chef Crumb has \(\frac{1}{2}\) of a pie left. A hungry troll eats \(\frac{1}{2}\) of that piece.
What fraction of the whole pie is left?
Think: What is half of one half?
Turn & talk with your table partner before we reveal! Slide 2 of 8
BRAIN FREEZE!
Wait... Multiplication makes things SMALLER?!
In Whole Number Land:
\(3 \times 4 = 12\)
Numbers get bigger! You have 3 groups of 4.
In Fraction Kitchen Land:
\(\frac{1}{2} \times \frac{1}{2} = \frac{1}{4}\)
The multiplication symbol \(\times\) means "OF"!
Chef Crumb's Giant Brownie Pan
\(\frac{1}{4}\)
Empty
Empty
Empty
You started with half of the pan, and took half of that. You now have one fourth!
Rule of Thumb: Multiplying by a fraction < 1 shrinks the size! Slide 3 of 8
VISUAL MODEL
The Area Grid Smash: \(\frac{2}{3} \times \frac{3}{4}\)
1
Slice Columns (First Fraction)
Cut vertically into 4 equal columns. Shade 3 columns blue (\(\frac{3}{4}\)).
2
Slice Rows (Second Fraction)
Cut horizontally into 3 equal rows. Shade 2 rows yellow (\(\frac{2}{3}\)).
3
Count the Overlap (Green!)
Overlap = 6 double-shaded boxes out of 12 total boxes = \(\frac{6}{12} = \frac{1}{2}\)!
\(\frac{3}{4}\) Columns \(\frac{2}{3}\) Rows Overlap
★
★
★
Row
★
★
★
Row
Col
Col
Col
Overlap = 6 / 12 = \(\frac{1}{2}\)
Blue meets Yellow makes Green: Double shaded is your answer! Slide 4 of 8
THE RECIPE
The Standard Algorithm: Top \(\times\) Top, Bottom \(\times\) Bottom!
No common denominators needed! Multiply straight across:
Numerator
Denominator
\(\times\)
Numerator
Denominator
=
Top \(\times\) Top
Bottom \(\times\) Bottom
Step 1
Multiply Tops
\(2 \times 3 = 6\)
Step 2
Multiply Bottoms
\(3 \times 4 = 12\)
Step 3
Simplify
\(\frac{6}{12} = \frac{1}{2}\)
Catchy chant: "Multiply straight across, then show that fraction who's boss!" Slide 5 of 8
WE DO
Chef Crumb's Recipe Testing
Whiteboards Ready!
Dish A: Goblin Garlic Bread
Chef Crumb has \(\frac{3}{5}\) loaf of garlic bread. He eats \(\frac{1}{2}\) of it.
\(\frac{1}{2} \times \frac{3}{5} = \text{?}\)
Whiteboard Steps:
• Multiply numerators across
• Multiply denominators across
Hold your board high when solved!
Dish B: Slug Slime Tart
The recipe needs \(\frac{2}{3}\) cup of slime. You only make \(\frac{3}{4}\) batch.
\(\frac{3}{4} \times \frac{2}{3} = \text{?}\)
Whiteboard Steps:
• Multiply straight across
• Don't forget to simplify to lowest terms!
Can you reduce your fraction?
Solve on your whiteboard! Teacher will reveal answers after all boards are up. Slide 6 of 8
PARTNER BATTLE
The Pickled Eyeball Casserole Showdown!
Two Strategies, One Dish!
A patron has \(\frac{4}{5}\) pan of casserole. A goblin eats \(\frac{1}{2}\) of their order.
Question: What fraction of the whole casserole pan did the goblin devour?
Equation to Solve: \(\frac{1}{2} \times \frac{4}{5} = \text{?}\)
PARTNER A Visual Grid Method
Draw an area grid model on your whiteboard:
Cut 5 vertical columns & shade 4 (\(\frac{4}{5}\))
Cut 2 horizontal rows & shade 1 (\(\frac{1}{2}\))
Count the double-shaded overlap boxes!
Target: Overlap Boxes / Total Boxes
PARTNER B Standard Algorithm
Multiply straight across on your whiteboard:
Multiply top \(\times\) top: \(1 \times 4\)
Multiply bottom \(\times\) bottom: \(2 \times 5\)
Reduce your answer to simplest form!
Target: Unsimplified \(\rightarrow\) Simplest Form
Compare boards with your partner! Did both methods lead to the exact same fraction? Slide 7 of 8
EXIT TICKET
Day 1 Kitchen Check-Out
Show What You Know!
Check #1: Solve & Simplify
Multiply straight across and reduce to simplest form:
\(\frac{2}{3} \times \frac{3}{5} = \text{?}\)
Write both the unsimplified fraction and the simplified answer on your exit slip.
Check #2: True or False?
Chef Crumb claims:
"Multiplying \(\frac{1}{3} \times \frac{1}{4}\) gives \(\frac{1}{12}\), which is bigger than \(\frac{1}{3}\)."
Is he correct or crazy? Explain in one sentence why or why not.
Rate your brain right now:
🟢 Mild (I got this!) 🟡 Medium (Need practice) 🔴 Extra Spicy (Help me!)
Slide 8 of 8
Monster Menu Practice Chef Crumb's Secret Menu
Day 1 Student Practice: Multiplying Fractions with Visuals
Name:
Date: Period:
GOLDEN RULE Multiply numerators across (top \(\times\) top) & denominators across (bottom \(\times\) bottom)!
\(\frac{a}{b} \times \frac{c}{d} = \frac{a \times c}{b \times d}\)
PART 1
The Visual Grid Smash: Shade & Solve
(Shade vertical columns in pencil, horizontal rows with stripes, count overlap!)
1. Ghost Pepper Sauce \(\frac{1}{3} \times \frac{2}{5}\)
• Columns shaded: 2 of 5
• Rows shaded: 1 of 3
• Overlap boxes: ___ of 15
Product: ______
2. Dragon Scale Chips \(\frac{3}{4} \times \frac{1}{2}\)
• Columns shaded: 1 of 2
• Rows shaded: 3 of 4
• Overlap boxes: ___ of 8
Product: ______
PART 2
Kitchen Computation: Multiply & Simplify
(Show your work straight across and reduce to simplest form)
3. Swamp Soda Mix Simplify!
\(\frac{2}{5} \times \frac{5}{6} =\)
Work:
Answer:
4. Melted Slime Drizzle Simplify!
\(\frac{3}{7} \times \frac{2}{3} =\)
Work:
Answer:
5. Crunchy Beetles Granola Simplify!
\(\frac{1}{4} \times \frac{8}{9} =\)
Work:
Answer:
6. Spider Silk Cotton Candy Simplify!
\(\frac{5}{8} \times \frac{4}{5} =\)
Work:
Answer:
Chef Crumb's Monster Diner Math Series • Grade 5 Page 1 of 2 (Continue on back)
PART 3
Monster Diner Story Scenarios
Read carefully, write an equation, and solve!
Scenario #7: The Cyclops Cupcake Disaster
Chef Crumb has \(\frac{4}{5}\) pound of powdered dragon bone sugar left in his jar. He uses \(\frac{3}{4}\) of what is left to dust a giant tray of Cyclops Cupcakes. How many pounds of powdered sugar did he use?
Multiplication Equation:
______ \(\times\) ______ = ______
Show Work & Simplify:
Sentence Answer:
Scenario #8: The Ogre's Bottomless Milkshake
An ogre customer orders a swamp milkshake that is \(\frac{2}{3}\) full. While the ogre looks away, a mischievous goblin slurps up \(\frac{3}{8}\) of what was in the cup. What fraction of the entire cup did the goblin slurp?
Multiplication Equation:
______ \(\times\) ______ = ______
Show Work & Simplify:
Sentence Answer:
PART 4
Find the Monster Mistake! (Error Analysis)
Apprentice Goblin Barnaby tried to solve \(\frac{2}{3} \times \frac{4}{5}\). Look at his work below:
Barnaby's Work:
🚨 Chef Crumb: "Barnaby, this soup tastes like math errors!"
1. What mistake did Barnaby make?
2. What is the CORRECT answer?
Chef Crumb's Monster Diner Math Series • Grade 5 Page 2 of 2
Diner Ticket Exit Ticket Customer Bill: Day 1 Exit Ticket
Multiplying Fractions Check-Out
Name: Date:
1. Solve & Model \(\frac{3}{4} \times \frac{2}{5} = \text{?}\)
Multiply straight across, then simplify to lowest terms:
Work:
Answer:
2. Troll Brownie Order
Chef Crumb has \(\frac{5}{6}\) of a brownie pan left. A hungry troll buys \(\frac{1}{2}\) of what is left. What fraction of the whole pan did the troll buy?
\(\frac{1}{2} \times \frac{5}{6} =\) Pan fraction:
Brain Status:
🟢 Mild (I got it!) 🟡 Medium (Need 1 more day) 🔴 Spicy (Brain melted)
CUT HERE (2 SLIPS PER PAGE)
Customer Bill: Day 1 Exit Ticket
Multiplying Fractions Check-Out
Name: Date:
1. Solve & Model \(\frac{3}{4} \times \frac{2}{5} = \text{?}\)
Multiply straight across, then simplify to lowest terms:
Work:
Answer:
2. Troll Brownie Order
Chef Crumb has \(\frac{5}{6}\) of a brownie pan left. A hungry troll buys \(\frac{1}{2}\) of what is left. What fraction of the whole pan did the troll buy?
\(\frac{1}{2} \times \frac{5}{6} =\) Pan fraction:
Brain Status:
🟢 Mild (I got it!) 🟡 Medium (Need 1 more day) 🔴 Spicy (Brain melted)
Slice and Dice Key TEACHER GUIDE
Day 1 Master Answer Key
Lesson 1: Fraction Slice & Dice (Visual Models & Algorithm)
Standard: CCSS 5.NF.B.4
Slideshow Problems Solution Reference
Slide 2: Spiral Warm-Up
• \(\frac{1}{2} + \frac{1}{4} = \frac{2}{4} + \frac{1}{4} = \mathbf{\frac{3}{4}}\)
• \(\frac{6}{8} \div \frac{2}{2} = \mathbf{\frac{3}{4}}\)
• Half of \(\frac{1}{2}\) pie = \(\mathbf{\frac{1}{4}}\) pie
Slide 6: Guided Practice
• Dish A: \(\frac{1}{2} \times \frac{3}{5} = \frac{1 \times 3}{2 \times 5} = \mathbf{\frac{3}{10}}\)
• Dish B: \(\frac{3}{4} \times \frac{2}{3} = \frac{6}{12} = \mathbf{\frac{1}{2}}\) cup
Slide 7 & 8: Duel & Exit
• Duel: \(\frac{1}{2} \times \frac{4}{5} = \frac{4}{10} = \mathbf{\frac{2}{5}}\)
• Exit #1: \(\frac{2}{3} \times \frac{3}{5} = \frac{6}{15} = \mathbf{\frac{2}{5}}\)
• Exit #2: False! \(\frac{1}{12}\) is smaller.
Practice Sheet Part 1: Visual Grid Smash Solutions
1. Ghost Pepper Sauce: \(\frac{1}{3} \times \frac{2}{5}\)
• Columns shaded: 2 of 5 (each column is \(\frac{1}{5}\))
• Rows shaded: 1 of 3 (each row is \(\frac{1}{3}\))
• Overlap boxes: 2 of 15 total boxes
Product = \(\frac{1 \times 2}{3 \times 5} = \mathbf{\frac{2}{15}}\) (already simplest form)
2. Dragon Scale Chips: \(\frac{3}{4} \times \frac{1}{2}\)
• Columns shaded: 1 of 2 (each column is \(\frac{1}{2}\))
• Rows shaded: 3 of 4 (each row is \(\frac{1}{4}\))
• Overlap boxes: 3 of 8 total boxes
Product = \(\frac{3 \times 1}{4 \times 2} = \mathbf{\frac{3}{8}}\) (already simplest form)
Practice Sheet Part 2: Kitchen Computation Solutions
3. Swamp Soda Mix:
\(\frac{2}{5} \times \frac{5}{6} = \frac{10}{30} \rightarrow \text{Divide by 10} = \mathbf{\frac{1}{3}}\)
(Cross-simplifying gives \(\frac{1}{1} \times \frac{1}{3} = \frac{1}{3}\))
4. Melted Slime Drizzle:
\(\frac{3}{7} \times \frac{2}{3} = \frac{6}{21} \rightarrow \text{Divide by 3} = \mathbf{\frac{2}{7}}\)
(Or cancel 3s immediately to get \(\frac{2}{7}\))
5. Crunchy Beetles Granola:
\(\frac{1}{4} \times \frac{8}{9} = \frac{8}{36} \rightarrow \text{Divide by 4} = \mathbf{\frac{2}{9}}\)
(Or \(\frac{8}{4} = 2\) in numerator, leaving \(\frac{2}{9}\))
6. Spider Silk Cotton Candy:
\(\frac{5}{8} \times \frac{4}{5} = \frac{20}{40} \rightarrow \text{Divide by 20} = \mathbf{\frac{1}{2}}\)
(Cancel 5s, \(\frac{4}{8} = \frac{1}{2}\))
Chef Crumb's Monster Diner Math Series • Grade 5 Answer Key • Page 1 of 2
Practice Sheet Parts 3 & 4 + Exit Ticket Key
Day 1 Solutions
Practice Sheet Part 3: Story Scenarios Solutions
Scenario #7: The Cyclops Cupcake Disaster
• Equation: \(\frac{3}{4} \times \frac{4}{5} = \frac{12}{20}\)
• Simplify: Divide top and bottom by 4 \(\rightarrow \mathbf{\frac{3}{5}}\)
• Complete Sentence: Chef Crumb used \(\frac{3}{5}\) pound of dragon bone sugar.
Scenario #8: The Ogre's Bottomless Milkshake
• Equation: \(\frac{3}{8} \times \frac{2}{3} = \frac{6}{24}\)
• Simplify: Divide top and bottom by 6 \(\rightarrow \mathbf{\frac{1}{4}}\)
• Complete Sentence: The goblin slurped up \(\frac{1}{4}\) of the entire cup.
Practice Sheet Part 4: Barnaby's Mistake Explained
1. Barnaby's Mistake: Barnaby added the denominators (\(3 + 5 = 8\)) instead of multiplying them! He also assumed he could just add because denominators had to combine.
2. Correct Solution: \(\frac{2}{3} \times \frac{4}{5} = \frac{2 \times 4}{3 \times 5} = \mathbf{\frac{8}{15}}\). (Cannot be simplified further).
Customer Bill (Exit Ticket) Solutions
Problem 1: Solve & Model
\(\frac{3}{4} \times \frac{2}{5} = \frac{6}{20} = \mathbf{\frac{3}{10}}\)
Students should show 4 rows \(\times\) 5 columns grid with 6 overlap boxes.
Problem 2: Troll Brownie Order
\(\frac{1}{2} \times \frac{5}{6} = \mathbf{\frac{5}{12}}\) of the whole pan.
Check that students multiplied straight across without cross-adding.
Teacher Tips & Common Misconceptions to Watch For:
Seeking Common Denominators: Students often try to find LCMs before multiplying. Remind them: "Multiplication goes straight across—no common denominators needed!" Adding Denominators: Watch out for Barnaby's error (\(b + d\) instead of \(b \times d\)).Size Confusion: Reinforce that multiplying by a proper fraction shrinks the quantity because you are taking a part of a part .
Chef Crumb's Monster Diner Math Series • Grade 5 Answer Key • Page 2 of 2
Monster Potion Slides Chef Crumb's Monster Diner
Grade 5 Math • Day 2
Level Up: Advanced Potion Chemistry!
Potion Mix &
The Ninja Cross-Slash
Master multiplying whole numbers, conquer mixed numbers, and unleash the cross-canceling ninja hack!
Today's Goal: Multiply whole numbers & mixed numbers with cross-simplifying
Slide 1 of 8
WARM-UP
Day 2 Spiral Potion Prep (3 Minutes)
Review & Reboot!
#1 Day 1 Flashback
Multiply straight across and reduce:
\(\frac{2}{3} \times \frac{3}{8} = ?\)
Top \(\times\) Top, Bottom \(\times\) Bottom
#2 Mixed to Improper
Convert to an improper fraction:
\(2\frac{1}{4} = ?\)
Hint: \((2 \times 4) + 1 = ?\)
#3 Repeated Addition
What is \(\frac{1}{3} + \frac{1}{3} + \frac{1}{3} + \frac{1}{3}\)?
\(4 \times \frac{1}{3} = ?\)
Can you write as mixed number?
Turn & share with your table partner before we reveal! Slide 2 of 8
SECRET TRICK #1
Multiplying Whole Numbers: "Put a 1 Under It!"
The Monster Dilemma:
"How do I multiply \(5 \times \frac{2}{3}\)? 5 doesn't have a bottom!"
Don't panic! Every whole number is secretly a fraction with a denominator of 1.
The Magic Transformation:
\(5\) \(\longrightarrow\) \(\frac{5}{1}\)
Now you have two fractions! Just multiply straight across.
Let's Brew 5 Batches of Slime Soup:
\(\frac{5}{1}\) \(\times\) \(\frac{2}{3}\) = \(\frac{10}{3}\)
• Top: \(5 \times 2 = \mathbf{10}\)
• Bottom: \(1 \times 3 = \mathbf{3}\)
• Convert: \(\frac{10}{3} = \mathbf{3\frac{1}{3}}\) cauldrons of soup!
Chant: "When you see a whole number on the run, slap it right on top of 1!" Slide 3 of 8
SECRET TRICK #2
The Ninja Cross-Slash: Simplify BEFORE You Multiply!
The Painful Giant Number Way:
\(\frac{7}{12} \times \frac{4}{21} = \frac{28}{252}\)
😱 Nobody wants to simplify \(\frac{28}{252}\)! Giant numbers are scary.
The Ninja Slash Way:
Look diagonally! If a top and a bottom share a factor, slash them down before multiplying!
Diagonals in Action
7¹ / 12³ \(\times\) 4¹ / 21³
⚔️ Slash 7 and 21 by 7: \(\mathbf{1}\) and \(\mathbf{3}\)
⚔️ Slash 4 and 12 by 4: \(\mathbf{1}\) and \(\mathbf{3}\)
Now multiply tiny numbers: \(\frac{1 \times 1}{3 \times 3} = \mathbf{\frac{1}{9}}\)!
Slash numbers down first to avoid giant math headaches! Slide 4 of 8
MIXED NUMBERS
Mixed Numbers Attack: Go M.A.D.!
You CANNOT multiply mixed numbers as they are! Turn them improper first:
M
Multiply
Whole \(\times\) Denominator
A
Add
Add the Numerator
D
Denominator
Denominator Stays Same!
\(2\frac{1}{3}\)
\(\longrightarrow\)
\((2 \times 3) + 1 = \mathbf{7}\)
\(\longrightarrow\)
\(\frac{7}{3}\)
Never multiply whole by whole and fraction by fraction—go MAD first! Slide 5 of 8
WE DO
Brewing Master Potions
Whiteboards Ready!
Potion A: Dragon Fire Brew
Each batch takes \(\frac{3}{4}\) jug of dragon sweat. Make 3 batches.
\(3 \times \frac{3}{4} = \text{?}\)
1. Put a 1 under: \(\frac{3}{1} \times \frac{3}{4}\)
2. Multiply: \(\frac{3 \times 3}{1 \times 4} = \frac{9}{4}\)
Answer: \(2\frac{1}{4}\) jugs of sweat!
Potion B: Swamp Shrek Shake
Multiply mixed number by fraction:
\(1\frac{1}{2} \times \frac{2}{5} = \text{?}\)
1. Go MAD: \(1\frac{1}{2} = \frac{3}{2}\)
2. Ninja slash 2s: \(\frac{3}{1} \times \frac{1}{5} = \frac{3}{5}\)
Answer: \(\frac{3}{5}\) cauldron!
Notice how ninja slashing the 2s made Problem B instant? Slide 6 of 8
YOU TRY
The 8-Eyeball Elixir Challenge!
Ninja Duel
Potion Master Grand Test:
"A master potion calls for \(2\frac{2}{3}\) jars of troll tears. You only need to brew \(\frac{3}{4}\) of a batch."
Go MAD on the mixed number, use ninja cross-canceling, and solve:
\(2\frac{2}{3} \times \frac{3}{4} = \text{___}\)
Step 1: Convert \(2\frac{2}{3}\)
\((2 \times 3) + 2 = \frac{8}{3}\)
Step 2: Multiply & Slash
\(\frac{8}{3} \times \frac{3}{4} = \frac{2 \times 1}{1 \times 1} = \mathbf{2}\) whole jars!
Did both 3s cancel out and 8 divide by 4 to make 2? You're a Potion Ninja! Slide 7 of 8
EXIT TICKET
Day 2 Potion Master Check-Out
Show Your Ninja Moves!
Check #1: Whole \(\times\) Fraction
Put a 1 under the whole number and solve:
\(6 \times \frac{2}{3} = \text{?}\)
Can you cross-cancel 6 and 3 first?
Check #2: Mixed Number MADness
Turn improper and multiply:
\(1\frac{3}{4} \times \frac{2}{7} = \text{?}\)
Hint: \(1\frac{3}{4} = \frac{7}{4}\). Look for diagonal ninja slashes!
Are you a Fraction Ninja?
🟢 Black Belt (Master!) 🟡 Green Belt (Almost there) 🔴 White Belt (Need practice)
Slide 8 of 8
Potion Panic Practice Potion Panic & Ninja Slashes
Day 2 Practice: Whole Numbers, Cross-Canceling & Mixed Numbers
Name:
Date: Period:
RULE 1 Whole Numbers: Slap a 1 under it! \(W = \frac{W}{1}\)
RULE 2 Ninja Slash: Simplify diagonals BEFORE multiplying!
PART 1
Whole Numbers \(\times\) Fractions ("Put a 1 Under It!")
1. Vampire Garlic Neutralizer Whole \(\times\) Fraction
\(4 \times \frac{3}{5} =\)
Rewrite as fraction: \(\frac{4}{1} \times \frac{3}{5}\)
Mixed Number Answer:
2. Werewolf Flea Shampoo Whole \(\times\) Fraction
\(8 \times \frac{1}{6} =\)
Rewrite as fraction: \(\frac{8}{1} \times \frac{1}{6}\)
Mixed Number Answer:
PART 2
Ninja Cross-Canceling Arena (Slash Before You Multiply!)
(Draw slash marks through shared factors)
3. Zombie Glow Juice
\(\frac{3}{10} \times \frac{5}{9} =\)
• Slash 3 & 9 by 3
• Slash 5 & 10 by 5
Product:
4. Bat Wing Broth
\(\frac{4}{7} \times \frac{14}{16} =\)
• Slash 4 & 16 by 4
• Slash 7 & 14 by 7
Product:
5. Mummy Dust Tonic
\(\frac{5}{12} \times \frac{8}{15} =\)
• Slash 5 & 15 by 5
• Slash 8 & 12 by 4
Product:
Chef Crumb's Monster Diner Math Series • Grade 5 Page 1 of 2 (Turn over for Mixed Numbers)
PART 3
Mixed Number MADness: Multiply Improper Fractions
Go M.A.D. first!
6. Cyclops Eye Drops Mixed \(\times\) Fraction
\(1\frac{1}{3} \times \frac{3}{8} =\)
1. Convert \(1\frac{1}{3}\) improper:
2. Multiply & cross-slash:
Final Answer:
7. Giant Stomp Elixir Mixed \(\times\) Mixed
\(2\frac{1}{2} \times 1\frac{1}{5} =\)
1. Convert both to improper:
2. Multiply & cross-slash:
Final Answer:
Part 4 • Potion Master Story Problem
Grand Wizard Gizzard brews a giant cauldron of Liquid Lightning. A full cauldron requires \(3\frac{1}{3}\) cups of charged storm water. Today, Gizzard only needs to brew \(\frac{3}{5}\) of a cauldron. How many cups of storm water does he need?
Equation (with improper fraction):
______ \(\times \frac{3}{5}\) = ______
Ninja Slash Work & Solution:
Sentence Answer:
PART 5
Goblin Barnaby Strikes Again! (Error Analysis)
Barnaby tried multiplying mixed numbers: \(2\frac{1}{2} \times 3\frac{1}{4}\).
Barnaby's "Hack": \((2 \times 3) + (\frac{1}{2} \times \frac{1}{4}) = 6 + \frac{1}{8} = 6\frac{1}{8}\)
1. Why is his shortcut illegal in math?
2. What is the true answer? (Go MAD!)
Chef Crumb's Monster Diner Math Series • Grade 5 Page 2 of 2
Potion Check Exit Ticket Potion Master: Day 2 Exit Ticket
Whole Numbers & Mixed Numbers Check
Name: Date:
1. Whole \(\times\) Fraction \(8 \times \frac{3}{4} = \text{?}\)
Put a 1 under it, ninja slash if you can, and solve:
Work:
Answer:
2. Mixed Number MADness \(2\frac{1}{4} \times \frac{2}{3} = \text{?}\)
Convert to improper fraction first, then multiply:
Work:
Answer:
Fraction Ninja Belt:
🥋 Black Belt (Master!) 🟢 Green Belt (Almost there) ⚪ White Belt (Need review)
CUT HERE (2 SLIPS PER PAGE)
Potion Master: Day 2 Exit Ticket
Whole Numbers & Mixed Numbers Check
Name: Date:
1. Whole \(\times\) Fraction \(8 \times \frac{3}{4} = \text{?}\)
Put a 1 under it, ninja slash if you can, and solve:
Work:
Answer:
2. Mixed Number MADness \(2\frac{1}{4} \times \frac{2}{3} = \text{?}\)
Convert to improper fraction first, then multiply:
Work:
Answer:
Fraction Ninja Belt:
🥋 Black Belt (Master!) 🟢 Green Belt (Almost there) ⚪ White Belt (Need review)
Monster Potion Key TEACHER GUIDE
Day 2 Master Answer Key
Lesson 2: Potion Mix, Cross-Canceling & Mixed Numbers
Standard: CCSS 5.NF.B.4 & 5.NF.B.6
Day 2 Slideshow Problem Solutions
Slide 2: Spiral Warm-Up
• \(\frac{2}{3} \times \frac{3}{8} = \frac{6}{24} = \mathbf{\frac{1}{4}}\)
• \(2\frac{1}{4} = \frac{(2 \times 4)+1}{4} = \mathbf{\frac{9}{4}}\)
• \(4 \times \frac{1}{3} = \frac{4}{3} = \mathbf{1\frac{1}{3}}\)
Slide 6: Guided Potions
• Potion A: \(3 \times \frac{3}{4} = \frac{9}{4} = \mathbf{2\frac{1}{4}}\) jugs
• Potion B: \(1\frac{1}{2} \times \frac{2}{5} = \frac{3}{2} \times \frac{2}{5} = \mathbf{\frac{3}{5}}\)
Slide 7 & 8: Duel & Exit
• Duel: \(\frac{8}{3} \times \frac{3}{4} = \frac{2 \times 1}{1 \times 1} = \mathbf{2}\) jars
• Exit #1: \(6 \times \frac{2}{3} = \frac{6}{1} \times \frac{2}{3} = \mathbf{4}\)
• Exit #2: \(\frac{7}{4} \times \frac{2}{7} = \frac{1 \times 1}{2 \times 1} = \mathbf{\frac{1}{2}}\)
Practice Sheet Part 1: Whole Numbers \(\times\) Fractions
1. Vampire Garlic Neutralizer: \(4 \times \frac{3}{5}\)
• Put 1 under whole number: \(\frac{4}{1} \times \frac{3}{5}\)
• Multiply straight across: \(\frac{4 \times 3}{1 \times 5} = \frac{12}{5}\)
Improper: \(\frac{12}{5}\) \(\longrightarrow\) Mixed: \(\mathbf{2\frac{2}{5}}\)
2. Werewolf Flea Shampoo: \(8 \times \frac{1}{6}\)
• Put 1 under whole number: \(\frac{8}{1} \times \frac{1}{6}\)
• Multiply: \(\frac{8}{6} \rightarrow\) reduce by 2 \(\rightarrow \frac{4}{3}\)
Improper: \(\frac{4}{3}\) \(\longrightarrow\) Mixed: \(\mathbf{1\frac{1}{3}}\)
Practice Sheet Part 2: Ninja Cross-Canceling Arena
3. Zombie Glow Juice:
\(\frac{3}{10} \times \frac{5}{9}\)
• Slash 3 & 9 by 3: \(1\) and \(3\)
• Slash 5 & 10 by 5: \(1\) and \(2\)
\(\frac{1 \times 1}{2 \times 3} = \mathbf{\frac{1}{6}}\)
4. Bat Wing Broth:
\(\frac{4}{7} \times \frac{14}{16}\)
• Slash 4 & 16 by 4: \(1\) and \(4\)
• Slash 7 & 14 by 7: \(1\) and \(2\)
\(\frac{1 \times 2}{1 \times 4} = \frac{2}{4} = \mathbf{\frac{1}{2}}\)
5. Mummy Dust Tonic:
\(\frac{5}{12} \times \frac{8}{15}\)
• Slash 5 & 15 by 5: \(1\) and \(3\)
• Slash 8 & 12 by 4: \(2\) and \(3\)
\(\frac{1 \times 2}{3 \times 3} = \mathbf{\frac{2}{9}}\)
Chef Crumb's Monster Diner Math Series • Grade 5 Answer Key • Page 1 of 2
Practice Sheet Parts 3-5 + Exit Ticket Key
Day 2 Solutions
Practice Sheet Part 3: Mixed Numbers Solutions
6. Cyclops Eye Drops: \(1\frac{1}{3} \times \frac{3}{8}\)
• Convert: \(1\frac{1}{3} = \frac{4}{3}\)
• Cross-slash 3s to 1, slash 4 & 8 by 4: \(1\) and \(2\)
• Result: \(\frac{1 \times 1}{1 \times 2} = \mathbf{\frac{1}{2}}\)
7. Giant Stomp Elixir: \(2\frac{1}{2} \times 1\frac{1}{5}\)
• Convert: \(2\frac{1}{2} = \frac{5}{2}\) and \(1\frac{1}{5} = \frac{6}{5}\)
• Cross-slash 5s to 1, slash 2 & 6 by 2: \(1\) and \(3\)
• Result: \(\frac{1 \times 3}{1 \times 1} = \mathbf{3}\) whole units!
Part 4: Liquid Lightning Potion
• Convert \(3\frac{1}{3} = \frac{10}{3}\)
• Equation: \(\frac{10}{3} \times \frac{3}{5}\)
• Cross-cancel 3s, \(\frac{10}{5} = 2\)
• Gizzard needs 2 cups of storm water.
Part 5: Barnaby's Error Debunked
• Why illegal: Multiplying mixed numbers requires distributive property (FOIL); multiplying only wholes and fractions ignores cross-products!
• True Answer: \(\frac{5}{2} \times \frac{13}{4} = \frac{65}{8} = \mathbf{8\frac{1}{8}}\) (Barnaby was off by 2 whole units!)
Day 2 Exit Ticket Solutions
Check 1: \(8 \times \frac{3}{4}\)
\(\frac{8}{1} \times \frac{3}{4} = \frac{2 \times 3}{1 \times 1} = \mathbf{6}\)
8 and 4 cross-cancel by 4 to leave 2 and 1.
Check 2: \(2\frac{1}{4} \times \frac{2}{3}\)
\(\frac{9}{4} \times \frac{2}{3} = \frac{3 \times 1}{2 \times 1} = \frac{3}{2} = \mathbf{1\frac{1}{2}}\)
9 and 3 cancel to 3 and 1; 2 and 4 cancel to 1 and 2.
Differentiation & Small Group Support:
Intervention: For students struggling with cross-canceling, allow them to multiply straight across first, then simplify using prime factors or GCF. Cross-canceling is an efficiency tool, not a mandatory barrier.
Extension: Challenge early finishers to multiply 3 fractions in a row: \(\frac{2}{3} \times \frac{3}{4} \times \frac{4}{5}\). Watch their eyes light up when all the middle numbers cancel out to leave \(\frac{2}{5}\)!
Chef Crumb's Monster Diner Math Series • Grade 5 Answer Key • Page 2 of 2
