Number Detective Worksheet
Grade 2 Math Topic: Operations Within 100 (No Regrouping)
Name:
Date:
Number Detective Worksheet
Read each case, show your detective thinking, and solve the mystery!
Page 1 of 2
Clue Strategy: 1 Circle numbers • 2 Underline question • 3 Choose + or − • 4 Label answer
Case 1 Addition Mystery
Join groups
Maya picked 24 red apples at the farm. Her brother picked 15 green apples. How many apples did they pick in all?
Show Your Work (Draw quick tens and ones)
Number Sentence
Final Answer
Answer: apples
Case 2 Subtraction Mystery
Take away
Sam had 58 colorful animal stickers. He gave 25 stickers to his best friend. How many stickers does Sam have left?
Show Your Work (Cross out ones and tens)
Number Sentence
Final Answer
Answer: stickers
Case 3 Total Mystery
Put parts together
The school library has 42 dog books and 36 cat books on display. How many animal books are there in all?
Show Your Work (Use standard or block method)
Number Sentence
Final Answer
Answer: books
Remember: Check that your ones and tens match your drawing! Turn to Page 2 for Mystery Addends ➔
Missing Addend Detective Part + Part = Total
Name:
Date:
Find the Missing Clue!
One number is hiding. Use what you know about the total to find it!
Page 2 of 2
Detective Secret: Start with what you know: part + ___ = total • Or subtract: total − part = missing part
Case 4 Missing Addend Mystery
How many more?
Liam needs 67 craft sticks to build a toy cabin. He already has 34 sticks. How many more craft sticks does Liam need?
Show Your Work (Count on or subtract)
Number Sentence
Final Answer
Answer: sticks
Case 5 Mystery Group
Some joined in
There were 21 birds singing in an oak tree. Some more birds flew in to join them. Now there are 55 birds in the tree. How many birds flew in?
Show Your Work (Find the missing part)
Number Sentence
Final Answer
Answer: birds
Case 6 Remaining Mystery
What is left?
Farmer Ben grew 89 pumpkins in his patch. He packed 46 pumpkins into his truck. How many pumpkins are still in the patch?
Show Your Work (Break into tens and ones)
Number Sentence
Final Answer
Answer: pumpkins
Detective Self-Check: I showed my work I wrote labels
Case Closed!