# The Mystery Number Hunt

This game lets you practice addition and subtraction within 100, just like we do in math class ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29844)). You will add three numbers together ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29848)), use a doubles or make-a-ten trick ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29850)), and check your answer with subtraction ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)). Have fun solving it!

## The puzzle

A secret number is hiding somewhere between 1 and 100.

Follow these three clues to find it.

**Clue 1:** Add three piles together: 10 stickers, 10 stickers, and 26 stickers. The total is the secret number.

**Clue 2:** If you add 4 to the secret number, you land exactly on a multiple of ten.

**Clue 3:** If you subtract the secret number from 100, the difference is 54.

What is the secret number?

## Hints

**Hint 1:** Start with Clue 1. Add the three piles in any order you like. The order does not change the total.

**Hint 2:** Once you have a number from Clue 1, add 4 to it. Does it land on a nice round number like 40 or 50?

**Hint 3:** Take your number and subtract it from 100. If the answer is 54, you found the secret number. If not, go back and check your first addition.

## Answer key

**The secret number is 46.**

Reasoning:

Clue 1: 10 + 10 + 26 = 46. You can add these in any order and still get 46, because the order of addends does not change the sum ([Knowledge](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29846)).

Clue 2: 46 + 4 = 50, a multiple of ten. This checks that 46 is correct.

Clue 3: 100 − 46 = 54. Subtracting is the inverse of adding, so this step verifies the answer ([Skills](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/29852)).

All three clues agree, so 46 is the secret number.All three clues agree, so 46 is the secret number.

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*AILI game · language en · model claude-sonnet-5 · generated 2026-09-17 · id 006c8c44-12f3-4010-82a1-460fd7403bfb*

### 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)
- resource:r1: Resources › type#activity, type#classroomactivity › MAT2, MAT3, MAT4, MAT5 (https://goa-cc-uat-aili-app-001.azurewebsites.net/library/resource/zcsdujXlaUa2uuq1-kBv0Q)