# Addition and Subtraction within 100

Students investigate addition and subtraction strategies for two-digit numbers ([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 add and subtract numbers up to 100, use doubles and multiples of ten, and check your work ([Details](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846)).

## Exercises

1. Add these numbers. Show your thinking by writing the tens and ones separately if it helps.

 23 + 14 = _______

2. Subtract. You can count up, count back, or break the numbers into tens and ones.

 47 − 15 = _______

3. Fill in the missing number.

 _______ + 12 = 38

4. Add three numbers. Remember, the order does not change the sum.

 5 + 20 + 15 = _______

5. Which number sentence is true?

 A) 32 + 8 = 41
 
 B) 32 + 8 = 40
 
 C) 32 + 8 = 39
 
 D) 32 + 8 = 42

6. Maya has 25 stickers. Her friend gives her 18 more stickers. How many stickers does Maya have now? Write a number sentence and solve.

 _______ + _______ = _______

## Answer Key

1. 37

2. 32

3. 26

4. 40

5. B

6. 25 + 18 = 43

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*AILI homework sheet · language en · model claude-haiku-4-5-20251001 · generated 2026-09-17 · id 9fd4e7cb-ff3f-4361-a8ef-1f456b61d9f9*

### 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)