Number Monster Slides
Number Monster Mystery
Can you help catch the Number Eater?
Number Detective Training
The Great Count
Let's count together from 1 to 20!
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
CRUNCH! MUNCH!
Oh no! Ben Eater the Number Eater is hungry. He's eating our numbers!
?
?
?
Watch: Ben Eater the Number Eater
Stop at 1:37
Embedded media
Detective Questions
What number comes...
AFTER 4?
4
?
What number comes...
BEFORE 15?
?
15
Counting On!
When a number is missing, start with the number you DO know and keep counting!
8
9
10
11
Time to Solve!
Pick up your Detective Worksheet!
Mystery Level: Rookie Detective
Number Detective Worksheet
Number Detectives
Case File: The Missing Numbers (1-20)
Name:
Date:
Mission Briefing
Oh no! The Number Eater was here! Look at the number strips. Use your "Counting On" strategy to find the missing numbers and save the day!
Case #1
4
5
7
Case #2
10
12
13
Case #3
14
15
16
SUPER SLEUTH CHALLENGE
17
20
Mystery Bonus!
What number comes after 19? Write it in the box!
Number Detective Lesson Plan
Number Monster Mystery
Grade Kindergarten
45 Minutes
Missing Numbers 1-20
Learning Objective
"Students will be able to identify missing numbers in a sequence (1-20) by counting forward using the 'counting on' strategy."
Materials
- Number Monster Slides
- Number Detective Worksheet
- Large physical Number Line (1-20)
- Pencils & Magnifying glasses (optional)
Video Reference
Ben Eater eats the numbers | Khan Academy
Stop at 1:37 for this specific lesson objective.
Lesson Procedure
5 MIN
Warm-up
The Great Choral Count
Gather students on the carpet. Use a large physical number line and point to each number as the class counts from 1 to 20 together.
Teacher Tip: Change your voice (whisper, giant voice, robot voice) every 5 numbers to keep them engaged!
10 MIN
Direct
Meet the Number Eater
Watch the video until 1:37. Pause when Sal and Esther suggest strategies.
Check for Understanding:
- "What number comes after 4?" (Encourage choral response)
- "What number comes before 15?" (Look at the number line)
- "What did Esther do when she didn't know the number? She used the numbers before it!"
15 MIN
Activity
Number Detectives
Hand out the Number Detective Worksheets. Explain that students are detectives helping Sal and Esther fix the grid.
Strategy Modeling: Model Case #1 on the board. "I see a 4, then a 5. I don't know what comes next! Let me count... 4, 5, ... 6! I'll write 6 in the box."
5 MIN
Closure
Mystery Solved!
Invite one student to share a "mystery" they solved. Have the whole class do the "Number Detective Handshake" (a high-five in the air).
Support & Extension
For Struggling Learners
Provide individual number lines for students to touch as they count. Work 1-on-1 to model the "next number" jump.
For Advanced Learners
Encourage them to finish the video (beyond 1:37) and identify the column patterns for higher numbers (10s place).