# Addition and Subtraction within 100

Students add and subtract two-digit numbers and explore strategies that make the work easier ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844), [Details](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846)). You will solve problems, check your answers, and find missing numbers.

## Exercises

1. Add these numbers. Show your work or draw a picture if it helps.

 23 + 14 = _____

2. Which number sentence is true?

 A) 35 + 20 = 54
 B) 35 + 20 = 55
 C) 35 + 20 = 56
 D) 35 + 20 = 57

3. Subtract.

 48 − 15 = _____

4. Fill in the missing number.

 16 + _____ = 42

5. Maya has 27 stickers. She gets 18 more stickers. How many stickers does Maya have now?

 _____ stickers

6. Check this answer using the opposite operation (inverse operation). Is it correct? Write yes or no.

 52 − 13 = 39

 Check: 39 + 13 = _____ Is the answer correct? _____

## Answer Key

1. 37

2. B) 35 + 20 = 55

3. 33

4. 26

5. 45 stickers

6. Check: 39 + 13 = 52 Is the answer correct? Yes

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*AILI homework sheet · language en · model claude-haiku-4-5-20251001 · generated 2026-09-17 · id e387c1ea-2c20-483a-92c3-fceecaaa04d6*

### Sources

- node:n1: Number: Quantity is measured with numbers that enable counting, labelling, comparing, and operating. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29820)
- node:n2: How can addition and subtraction be interpreted? (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29843)
- node:n3: Students investigate addition and subtraction within 100. (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844)
- node:n4: Details (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846)