Fraction Doctor Lesson Plan Mixed Number Surgery
Grade 5 Math • Fractions & Decimals
60 MINUTES
Learning Objective
Students will identify and correct errors involving improper fractions in mixed number sums, ensuring all results are expressed in simplest form as proper mixed numbers.
Materials Needed
Individual Whiteboards & Markers
Error Doctor Worksheet (1 per student)Red Pens (for "Surgery")
Projector/Smartboard for Video
Poster Paper (for Extension)
Video Reference
Title: Addition of Mixed Numbers (1)
URL: https://www.youtube.com/watch?v=HBOMrd-qZNI
Focus: 1:05 - End (Examples 2 & 3)
Instructional Sequence
WARM-UP 5m
The "Quick Check-up"
Review converting improper fractions to mixed numbers using whiteboards. Prompt students with:
\( \frac{5}{4} \)
\( \frac{3}{2} \)
\( \frac{7}{5} \)
VIDEO 15m
Expert Consultation
Watch from 1:05 . Use the following pause points for deep discussion:
1:35 Pause when \( 7 \frac{7}{5} \) appears. Ask: "Is this finished? What looks 'sick' or 'wrong' about this number?"
1:38-1:50 Focus on the breakdown of \( \frac{7}{5} \rightarrow 1 \frac{2}{5} \) and how that '1' joins the '7'.
2:24 Pause at \( 8 \frac{12}{8} \). Have students predict the next TWO steps (Convert improper AND simplify).
ACTIVITY 20m
The Error Doctor
Distribute the Error Doctor Worksheet and Red Pens .
Students must review "patient files" (math problems).
They diagnose if the problem is "Healthy" (Correct) or "Needs Surgery" (Improper fraction left in sum).
For those needing surgery, students use their red pen to show the conversion and final answer.
EXTEND 20m
The Healing Poster
Students work in pairs to create an infographic poster explaining why \( 4 \frac{5}{4} \) is actually \( 5 \frac{1}{4} \). They should use visual models (rectangles or circles) to show the "extra" whole being created.
Mixed Number
Integer + Proper Fraction
Improper Fraction
Numerator \(\ge\) Denominator
Like Fractions
Same Denominator
Simplifying
Reducing to lowest terms
Mixed Number Surgery Slides Mixed Number Surgery
Report to the O.R. — It's time to heal some fractions!
Grade 5 Math The Error Doctor
Quick Check-up
Case #1
\( \frac{5}{4} \)
Write as mixed number
Case #2
\( \frac{3}{2} \)
Write as mixed number
Case #3
\( \frac{7}{5} \)
Write as mixed number
Raise your whiteboards in 3... 2... 1...!
Expert Consultation
WATCH: 1:05 - END
Embedded media
Surgery Discussion
1:35
The Diagnosis
"Look at \( 7 \frac{7}{5} \). Why can't we leave it like this? What is 'wrong' with the fraction?"
2:24
Predict the Procedure
The answer is \( 8 \frac{12}{8} \). We need TWO steps to fix it. Can you guess them?
The Error Doctor
1
Check each patient file (problem).
2
Diagnose: Is the sum proper or improper?
3
Use your Red Pen to perform surgery.
Example File
\( 4 \frac{5}{4} \)
\( 5 \frac{1}{4} \)
The Healing Poster
Work with a partner to create a visual guide showing HOW \( 4 \frac{5}{4} \) becomes \( 5 \frac{1}{4} \).
Requirement 1
Color Models
Requirement 2
Step-by-Step
Requirement 3
Catchy Title
Error Doctor Worksheet The Error Doctor
Resident Name:
Date of Surgery:
Mission: You are the lead surgeon. Review the patient files below. Identify sums that were left as improper fractions (the "Errors"). Use your Red Pen to perform surgery and heal the numbers.
File #101
\( 2 \frac{1}{4} + 1 \frac{3}{4} = \) \( 3 \frac{4}{4} \)
Diagnosis
Healthy
Sick
Surgery Needed?
File #102
\( 1 \frac{2}{5} + 3 \frac{1}{5} = \) \( 4 \frac{3}{5} \)
Diagnosis
Healthy
Sick
Surgery Needed?
File #103
\( 4 \frac{4}{7} + 2 \frac{6}{7} = \) \( 6 \frac{10}{7} \)
Diagnosis
Healthy
Sick
Surgery Needed?
File #104
\( 3 \frac{5}{8} + 1 \frac{7}{8} = \) \( 4 \frac{12}{8} \)
Diagnosis
Healthy
Sick
Surgery Needed?
File #105
\( 5 \frac{2}{3} + 2 \frac{2}{3} = \) \( 7 \frac{4}{3} \)
Diagnosis
Healthy
Sick
Surgery Needed?
File #106
\( 2 \frac{1}{6} + 4 \frac{4}{6} = \) \( 6 \frac{5}{6} \)
Diagnosis
Healthy
Sick
Surgery Needed?
Surgeon's Reflection
Why is a number like \( 7 \frac{4}{3} \) considered "sick" in math? What is the secret to healing it?
Error Doctor Answer Key Surgery Record Key
Teacher Resource
File #101
\( 2 \frac{1}{4} + 1 \frac{3}{4} = 3 \frac{4}{4} \)
Treatment Plan
Diagnosis: Sick (\( \frac{4}{4} \) is a whole)
File #102
\( 1 \frac{2}{5} + 3 \frac{1}{5} = 4 \frac{3}{5} \)
Treatment Plan
Diagnosis: Healthy
File #103
\( 4 \frac{4}{7} + 2 \frac{6}{7} = 6 \frac{10}{7} \)
Treatment Plan
Diagnosis: Sick (\( \frac{10}{7} = 1 \frac{3}{7} \))
File #104
\( 3 \frac{5}{8} + 1 \frac{7}{8} = 4 \frac{12}{8} \)
Treatment Plan
Diagnosis: Sick (\( \frac{12}{8} = 1 \frac{4}{8} \))
File #105
\( 5 \frac{2}{3} + 2 \frac{2}{3} = 7 \frac{4}{3} \)
Treatment Plan
Diagnosis: Sick (\( \frac{4}{3} = 1 \frac{1}{3} \))
File #106
\( 2 \frac{1}{6} + 4 \frac{4}{6} = 6 \frac{5}{6} \)
Treatment Plan
Diagnosis: Healthy
Grading Focus
Diagnosis Mastery Student correctly identifies 4 sick and 2 healthy patients.
Conversion Skill Student correctly breaks improper fraction into mixed number before adding to whole sum.
Precision Final sums are simplified (e.g., \( 5 \frac{1}{2} \) instead of \( 5 \frac{4}{8} \)).
