Problem 10 · Rotom’s Pokédex RectanglePrint one blank worksheet now, download its PDF, or prepare a family or classroom packet.

MathJewels.com

Name

Date

Rotom’s Pokédex Rectangle

Complete to collectPolished QuartzLevel 3 · 5 Glints

A Pokédex is an electronic guide to Pokémon. Rotom’s screen shows a 1–100 number chart: 1–10 in the first row, 11–20 in the second, and so on. You do not need to know the characters; their names label the four corners of a rectangle whose sides follow chart rows and columns. Eevee and Squirtle label opposite corners. Their hidden numbers add to 69.

Every rectangle uses four different corners.

Your challenge

What is the total of all four hidden numbers? Explain why your total is forced for every possible rectangle, not just the one pictured.

Show your answer

Use an equation and the chart’s structure. You do not need to find each hidden number. On separate paper, write the total, one equation, and the reason it works for every rectangle.

Theme

Pokémon

Skills

Grade

Grade 2

Math area

Topics

Math readiness

Designed for Grade 2

Uses Middle Grade 2 math.

Thinking

Stretch challenge

A nontrivial plan using familiar mathematical ideas.

Time & response

About 4–12 minutes

Moderate amount of written work · Proof response.

How to support: Ask the learner to compare the two diagonal totals, but do not name the relationship.

Precise MJD coordinates, factor scores, skill weights, calibration evidence, and curriculum crosswalks. This reference is available to everyone and is intentionally last.

Content level

MJ 2.5

Grades K–2

Grade 2 progression · point 5

Likely range: MJ 2.5–2.8
Confidence: 90%

Challenge

C3 · Stretch

A nontrivial plan using familiar mathematical ideas.

Method selection2
Reasoning depth2
Novelty1
Constraint management2
Proof or justification2

Workload

W2 · Moderate

Several coordinated calculations, representations, or explanation steps.

Active time: 4–12 minutes · typically 7
Response: Proof
Known-method steps: 5

Mechanical execution1
Written output2
Representation production1
Bookkeeping1

Learning focus

Skills this problem practices

What a successful response demonstrates, with each skill’s share of the content rating.

Use hundred-chart structure
The learner can use hundred-chart structure. The capability is credited only when the task makes that demand necessary for success.
- Independent mastery
- 70% focus
- MJ 2.5 milestone
Solve one- and two-step addition/subtraction stories within 100
The learner can solve one- and two-step addition/subtraction stories within 100. This capability is distinct from mere exposure to or isolated use of Grade 1 story structures.
- Independent mastery
- 30% focus
- MJ 2.3 milestone

External alignment

Curriculum and standards crosswalks

Approved evidence-backed locations that support discovery. They do not define the MathJewels rating.

Bridges in Mathematicsthird-edition · 16 locations

Modules9 locations · Representative: Module 3: Exploring Place Value & 3-Digit Numbers

Module 4: Adding & Subtracting to 20
grade-2-unit-1-module-4
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Unit 1, Module 4, Sessions 4
- Partial
- Develops
- Overlapping
- Medium Confidence
Module 2: Adding & Subtracting on the Number Line
grade-2-unit-3-module-2
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Unit 3, Module 2, Sessions 1, 2
- Partial
- Develops
- Overlapping
- Medium Confidence
Module 3: Posing & Solving Contextual Problems
grade-2-unit-3-module-3
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Unit 3, Module 3, Sessions 1, 3, 4, 5, 7
- Partial
- Develops
- Overlapping
- Medium Confidence
Module 4: Data & the Color Tiles Project
grade-2-unit-3-module-4
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Unit 3, Module 4, Sessions 1
- Partial
- Develops
- Overlapping
- Medium Confidence
Module 3: Jessie & the Giant
grade-2-unit-4-module-3
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Unit 4, Module 3, Sessions 2, 5, 6
- Partial
- Develops
- Overlapping
- Medium Confidence
Module 4: Thinking in 3s
grade-2-unit-4-module-4
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Unit 4, Module 4, Sessions 1, 2
- Partial
- Develops
- Overlapping
- Medium Confidence
Module 3: Exploring Place Value & 3-Digit Numbers
grade-2-unit-5-module-3
The exact rectangle proof extends the structural and sequence work in the cited sessions.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Pages 3 and 6, Unit 5 Module 3, Sessions 3 and 5
- Partial
- Develops
- Overlapping
- Independent
- High Confidence
Module 4: Sequences & Growing Patterns
grade-2-unit-5-module-4
The exact rectangle proof extends the structural reasoning in the cited session.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 3, Unit 5 Module 4, Session 2
- Partial
- Develops
- Overlapping
- Independent
- High Confidence
Module 4: Exploring Equal Parts & Groups
grade-2-unit-7-module-4
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Unit 7, Module 4, Sessions 1
- Partial
- Develops
- Overlapping
- Medium Confidence

Number Corner workouts7 locations · Representative: February: Computational Fluency

September: Calendar Grid
grade-2-number-corner-september-calendar-grid
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Number Corner September, Calendar Grid
- Partial
- Develops
- Overlapping
- Medium Confidence
February: Computational Fluency
grade-2-number-corner-february-computational-fluency
This Number Corner workout supports structural reasoning used by the exact item.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 3, February Computational Fluency
- Partial
- Develops
- Overlapping
- Independent
- High Confidence
February: Number Line
grade-2-number-corner-february-number-line
This Number Corner workout supports the sequence structure; the invariant proof is an extension.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Pages 3 and 6, February Number Line
- Partial
- Develops
- Overlapping
- Independent
- High Confidence
March: Number Line
grade-2-number-corner-march-number-line
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Number Corner March, Number Line
- Partial
- Develops
- Overlapping
- Medium Confidence
April: Number Line
grade-2-number-corner-april-number-line
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Number Corner April, Number Line
- Partial
- Develops
- Overlapping
- Medium Confidence
May: Calendar Grid
grade-2-number-corner-may-calendar-grid
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Number Corner May, Calendar Grid
- Partial
- Develops
- Overlapping
- Medium Confidence
May: Calendar Collector
grade-2-number-corner-may-calendar-collector
The official publisher correlation lists this curriculum location for 2.OA.A.1, which resolves from the MathJewels capability's recorded CCSS locator. The mapping is partial because a curriculum location can develop more than this single capability.
- Bridges & Number Corner Third Edition: Grade 2 Correlations to the Common Core State Standards · Page 5, standard 2.OA.A.1: Number Corner May, Calendar Collector
- Partial
- Develops
- Overlapping
- Medium Confidence

Common Core State Standards for Mathematics2010 · 3 locations

Standards1 location · Representative: Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.
CCSS.MATH.CONTENT.2.OA.A.1
Solve one- and two-step addition/subtraction stories within 100 was reviewed against CCSS.Math.Content.2.OA.A.1. The ontology's CCSS locator 2.OA.A.1 resolves to this standard; the atomic skill is narrower relative to the published expectation.
- Strong
- Assesses
- Narrower
- Independent
- Medium Confidence

Practice locations2 locations · Representative: Look for and make use of structure.

Look for and make use of structure.
CCSS.MATH.PRACTICE.MP7
The rectangle invariant requires the learner to identify and justify structure that is specific to this exact item.
- Partial
- Develops
- Overlapping
- Transfer
- High Confidence
Look for and express regularity in repeated reasoning.
CCSS.MATH.PRACTICE.MP8
The proof generalizes repeated horizontal and vertical changes in this exact number-chart construction.
- Partial
- Develops
- Overlapping
- Transfer
- High Confidence