# Grade 2 Mathematics: 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)). Familiar number facts and strategies such as making multiples of ten and using doubles support addition and subtraction of two-digit numbers ([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)). A sum can be composed in multiple ways, including with more than two addends, and the order of addends does not change the sum ([Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29847), [Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29847), [Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846), [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)). Addition and subtraction can represent the sum or difference of countable quantities or measurable lengths, and students recall facts, apply strategies, verify answers using inverse operations, find missing quantities, and solve problems within 100 ([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), [Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)).

## Rubric

| Criterion | Beginning | Developing | Proficient | Exemplary |
|---|---|---|---|---|
| Number facts and strategies | Recalls few addition or subtraction facts to 10; strategies are missing or unclear ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)). | Recalls some facts to 10; names one strategy such as doubles or making ten, with some errors ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)). | Recalls addition facts to 10 and related subtraction facts; applies making-ten or doubles strategies correctly ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). | Recalls facts fluently and explains why a strategy such as making ten works for two-digit numbers ([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/29852)). |
| Composing sums to 100 | Shows one way to make a sum; does not show 100 as tens ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)). | Shows two ways to compose a sum; attempts to show 100 as multiples of 10. | Shows multiple ways to compose a sum, including with more than two addends, and 100 as tens ([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), [Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29847)). | Shows several sums for 100, uses more than two addends, and explains how regrouping which addends are combined first does not change the sum ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846), [Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846)). |
| Calculating and verifying | Adds or subtracts within 100 with many errors; does not check answers ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). | Adds numbers to a sum of 100 or subtracts with a minuend to 100 with occasional errors; checking is incomplete ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). | Adds and subtracts accurately within 100 and verifies the answer using the inverse operation ([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)). | Accurately solves problems within 100, verifies with inverse operations, and finds missing quantities in a sum or difference ([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)). |
| Representing quantities and lengths | Model or report does not clearly show a quantity or length being combined or separated ([Understanding](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29851)). | Model or report shows a quantity or length problem, but labels are incomplete ([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)). | Model or report clearly represents addition or subtraction of countable quantities or measurable lengths, with labels ([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)). | Model or report represents both quantities and lengths, with clear labels and a solved, checked problem ([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)). |

## 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.

A total of 4 to 6 points suggests the student is Beginning overall. A total of 7 to 10 points suggests Developing. A total of 11 to 13 points suggests Proficient. A total of 14 to 16 points suggests Exemplary.

Use the total as a guide, not a rule. A student strong in three criteria but weak in one may still need targeted support in that area.

## Notes for the teacher

- Mark each criterion based on the evidence provided. Look for clear demonstration of the strategy or concept named in the descriptor.
- Look for the making-ten or doubles strategy by name or by clear picture, not just a correct answer ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)).
- For the composing sums criterion, composing a sum in multiple ways, including with more than two addends, is required. A model with only two addends does not meet the Proficient descriptor and caps at Developing ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)).
- For the Exemplary descriptor on composing sums, accept evidence that shows how regrouping which addends are combined first (the associative property) does not change the sum. Addition and subtraction strategies for two-digit numbers include making multiples of ten and using doubles.
- Keep a few sample reports at each level to check your own marking stays consistent from student to student.

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*AILI marking guide · language en · model claude-sonnet-5 · generated 2026-09-17 · id 20f7941a-7a92-495e-b60a-86a7d153db4e*

### 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? › Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)
- 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? (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844)
- 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)