# Addition and Subtraction Within 100: Marking Guide

## Task

Students present a labelled model or report on addition and subtraction within 100.

## Curriculum alignment

This task assesses the following outcomes:

- Students investigate addition and subtraction within 100 ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844)).
- Students recall addition facts with addends to 10 and related subtraction facts, and add numbers up to a sum of 100 and subtract with a maximum minuend of 100 ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)).
- Students visualize 100 as a composition of multiples of ten and compose a sum in multiple ways, including with more than two addends ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)).
- Students apply strategies such as making multiples of ten and using doubles, and understand that familiar number facts support these strategies ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850), [Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)). This connects to [Resource](https://goa-cc-uat-aili-app-001.azurewebsites.net/library/resource/0NK9kueDjkiTuLghkTw7gA).
- Students verify a sum or difference using inverse operations, and determine a missing quantity in a sum or difference within 100 ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)).
- Students understand that addition and subtraction can represent sums or differences of countable quantities or measurable lengths, and solve problems using this idea ([Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)).

## Rubric

| Criterion | Beginning | Developing | Proficient | Exemplary |
|---|---|---|---|---|
| Number facts and calculation within 100 | Adds or subtracts only with help. Many facts to 10 are missed ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). | Recalls some facts to 10. Adds or subtracts two-digit numbers with errors ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). | Recalls facts to 10 and adds to a sum of 100, subtracts with minuend to 100, mostly correct ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). | Recalls facts fluently and calculates within 100 accurately and quickly ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). |
| Strategy use (tens, doubles, composing sums) | Shows no clear strategy. Model does not show tens or doubles ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)). | Names a strategy but uses it inconsistently, such as tens or doubles ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850), [Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)). | Uses making-ten and doubles strategies correctly to solve problems ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)). | Explains and compares more than one strategy, including composing a sum with more than two addends ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)). |
| Composing and visualizing 100 | Cannot show 100 as groups of ten. Model is unclear or missing ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)). | Shows 100 as tens with some errors, such as miscounting groups ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)). | Visualizes 100 as multiples of ten in at least one correct way ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29847)). | Shows 100 as multiples of ten in several different ways, all correct ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29847)). |
| Verifying and applying to problems | Does not check work. Cannot connect addition or subtraction to a real problem ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851)). | Attempts to verify with inverse operations but makes errors. Problem link is unclear ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). | Verifies a sum or difference correctly using inverse operations and solves a quantity or length problem ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851)). | Verifies work independently, finds a missing quantity in varied ways, and solves problems clearly with quantities or lengths ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851)). |

## Scoring

Score each criterion at one level: Beginning (1 point), Developing (2 points), Proficient (3 points), or Exemplary (4 points).

Add the four scores for a total out of 16.

- 4 to 7: Beginning overall
- 8 to 10: Developing overall
- 11 to 13: Proficient overall
- 14 to 16: Exemplary overall

A student does not need every criterion at the same level to reach an overall band. Use the total score as the primary guide, but check that no single criterion sits far below the others before assigning the overall level.

## Notes for the teacher

- Look for the strategy in the student's own words or drawings, not just the final answer. A correct sum with no visible strategy should not score above Developing on strategy use.
- When a model shows one correct way to compose 100, mark it Proficient on that criterion even if the report as a whole is uneven.
- Students investigate addition and subtraction within 100. Check that any borrowed problems still test addition and subtraction within 100, not beyond it.
- Apply the same threshold for "mostly correct" across all students: allow one or two calculation slips at Proficient, but reserve Exemplary for accurate, independent work.

---
*AILI marking guide · language en · model claude-sonnet-5 · generated 2026-09-17 · id 46177ce8-eb20-4d1b-82b7-4af1676a0345*

### Sources

- node:n1: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29843)
- node:n2: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844)
- node:n3: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846)
- node:n4: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)
- node:n5: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29847)
- node:n6: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)
- node:n7: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)
- node:n8: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851)
- node:n9: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)
- node:n10: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)
- node:n11: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844)
- node:n12: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)
- node:n13: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29847)
- node:n14: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851)
- node:n15: Mathematics › Mathematics (K–6) › Grade 2 › Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. › How can addition and subtraction be interpreted? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846)
- resource:r1: Resources › type#assessment, type#lessonplan › MAT2 (https://goa-cc-uat-aili-app-001.azurewebsites.net/library/resource/0NK9kueDjkiTuLghkTw7gA)