Base Ten Builder Slides Lesson 1 Place Value Foundations
Double Digit Detectives
Build It with Tens & Ones
Every two-digit number is made of two special teams: groups of ten and single leftovers!
Tens Rod
1 rod = 10 single units
Ones Unit
1 cube = 1 single unit
Focus: Concrete Base-Ten Models Slide 1 of 3
Step 1 Place Value Chart
Standard Form
Counting the Blocks to Write the Number
Build-It Visual
3 tens and 4 ones
Tens
Ones
3
4
Standard Form: 34
The tens digit tells how many rods; the ones digit tells how many cubes! Slide 2 of 3
Guided Check Classroom Challenge
Can you spot the number?
What Double-Digit Number Is Built?
Mystery A
5 tens + 2 ones = 52
Mystery B
2 tens + 7 ones = 27
Ready to build with your practice worksheet! Slide 3 of 3
Block Squad Worksheet Lesson 1 Practice
Block Squad Worksheet
Name:
Date:
Count the tens rods (rods = 10) and ones units (cubes = 1). Write the counts and the standard double-digit number!
1
Count the Blocks & Write Standard Form
Tens:
Ones:
Standard:
Tens:
Ones:
Standard:
(no cubes)
Tens:
Ones:
Standard:
2
Build It: Draw Rods & Units
Hint: Draw tall lines | for tens and small dots • for ones
Number: 47
Tens: Ones:
Number: 29
Tens: Ones:
Number: 63
Tens: Ones:
Detective Riddle Challenge
"I have 7 tens and 1 one. What number am I?"
"I have 8 tens and 0 ones. What number am I?"
Double Digit Detectives • Unit 1 Tens Rods = 10 • Ones Cubes = 1 Page 1 of 1
Block Squad Answer Key Teacher Guide • Answer Key
Block Squad Answer Key
Grading Key
Teacher Tip: Watch for students reversing digits (e.g., writing 53 instead of 35). Remind them that rods are tens (first digit) and cubes are ones (second digit).
1
Part 1 Answers: Count & Standard Form
3 rods (30)
Tens: 3
Ones: 5
Standard: 35
4 rods (40)
Tens: 4
Ones: 2
Standard: 42
6 rods (60)
Tens: 6
Ones: 0
Standard: 60
2
Part 2 Answers: Build It Drawings
Number: 47
| | | |
• • • • • • •
Tens: 4 Ones: 7
Number: 29
| |
••••• ••••
Tens: 2 Ones: 9
Number: 63
| | | | | |
• • •
Tens: 6 Ones: 3
Part 3 Answers: Detective Riddles
7 tens and 1 one
70 + 1
71
8 tens and 0 ones
80 + 0
80
Double Digit Detectives • Answer Key Total Points: 8 Items Page 1 of 1
Expanded Power Slides Lesson 2 Expanded & Word Forms
Double Digit Detectives
Unpack the Value: Expanded Form
Expanded form breaks a number apart to show the real mathematical value of each digit!
Standard Form
58
=
5 Tens Value
50
8 Ones Value
8
Key Rule: 5 tens isn't just 5, it is 50! Slide 1 of 3
Spelling Secret Word Form
Say It, Write It!
Writing Numbers with Hyphens (-)
When writing numbers from 21 to 99, we join the tens word and the ones word with a hyphen!
36
30 + 6
thirty-six
42
40 + 2
forty-two
75
70 + 5
seventy-five
Spelling alert: "forty" has no 'u', unlike "fourteen"! Slide 2 of 3
Team Match Connect the Three Forms
Standard • Expanded • Word
See the Three Forms in Action
64 60 + 4 sixty-four
81 80 + 1 eighty-one
90 90 + 0 ninety
Now open your Word Unpacker practice worksheet! Slide 3 of 3
Word Unpacker Worksheet Lesson 2 Practice
Word Unpacker Worksheet
Name:
Date:
Unpack double-digit numbers into expanded form equations and practice spelling their word forms using the helper bank!
Number Word Helper Bank
Tens: twenty (20) • thirty (30) • forty (40) • fifty (50) • sixty (60) • seventy (70) • eighty (80) • ninety (90)
Ones: one (1) • two (2) • three (3) • four (4) • five (5) • six (6) • seven (7) • eight (8) • nine (9)
1
Unpack It: Write in Expanded Form
37 =
52 =
84 =
90 =
2
Pack It Up: Write in Standard Form
40 + 6 =
70 + 9 =
20 + 8 =
60 + 0 =
3
Word Form Detective: Write the Words
Remember the hyphen (-)
45 (40 + 5)
68 (60 + 8)
23 (20 + 3)
Double Digit Detectives • Unit 2 Expanded: Tens Value + Ones Value • Words: Tens-Ones Page 1 of 1
Word Unpacker Answer Key Teacher Guide • Answer Key
Word Unpacker Answer Key
Grading Key
Teacher Tip: Watch for the common error where students write digits instead of place values in expanded form (e.g., writing 3 + 7 instead of 30 + 7 for 37). Emphasize that the first number must show the tens value!
1
Part 1 Answers: Expanded Form
37 =
30 + 7
52 =
50 + 2
84 =
80 + 4
90 =
90 + 0
2
Part 2 Answers: Standard Form
40 + 6 = 46
70 + 9 = 79
20 + 8 = 28
60 + 0 = 60
3
Part 3 Answers: Word Form Spellings
45 (40 + 5)
forty-five
68 (60 + 8)
sixty-eight
23 (20 + 3)
twenty-three
Double Digit Detectives • Answer Key Total Points: 11 Items Page 1 of 1
All Forms Arena Slides Lesson 3 Five Forms Synthesis
Double Digit Detectives
The Five Forms Arena
True number detectives can show any double-digit number in five different mathematical ways!
Form 1
Standard
34
Form 2
Expanded
30 + 4
Form 3
Build It
3 rods 4 cubes
Form 4
Word Form
thirty-four
Form 5
Tallies
Groups of 5
Mastering multiple representations builds flexible mathematical thinking! Slide 1 of 3
Special Focus Tallies for Double Digits
Counting by 5s
Bundle Up in Fives!
Every bundle of 5 has 4 standing sticks and 1 diagonal cross strike!
Target Number: 23 Count by 5s: 5, 10, 15, 20... + 3 singles!
||||
5
||||
10
||||
15
||||
20
|||
23
Each group of 10 needs exactly two bundles of 5! Slide 2 of 3
Grand Finale The Complete Number Mat
Number: 42
One Number, Five Powerful Views
Standard & Words
42 • forty-two
Expanded Form
40 + 2
Build-It Base Ten
4 rods & 2 units
Tally Marks
8 bundles + ||
Time to solve the final Number Mat Worksheet! Slide 3 of 3
Number Mat Worksheet Lesson 3 • Master Challenge
Number Mat Worksheet
Name:
Date:
Show each double-digit number across all 5 representations : Standard, Word, Expanded, Build-It, and Tallies!
MAT 1 Target Number: 34
Complete all 4 quadrants below
1. Word Form
Include the hyphen (-)
2. Expanded Form
tens value + ones value
3. Build-It (Base Ten) | = 10, • = 1
4. Tally Marks Bundle groups of 5
MAT 2 Clue Given: 50 + 6
Find the number and complete all forms
1. Standard Form
Write the two-digit number
2. Word Form
Include the hyphen (-)
3. Build-It (Base Ten) | = 10, • = 1
4. Tally Marks Bundle groups of 5
Quick Match: Which tally count equals 25 ?
A) 3 bundles of 5 B) 5 bundles of 5 C) 2 bundles of 5 + 3
Choice:
Double Digit Detectives • Unit 3 Capstone Standard • Expanded • Build-It • Word • Tallies Page 1 of 1
Number Mat Answer Key Teacher Guide • Answer Key
Number Mat Answer Key
Master Key
Teacher Tip: For tally marks, encourage students to count by 5s aloud: "5, 10, 15, 20..." Each 10 is always 2 tally bundles.
MAT 1 KEY Target Number: 34
4 Points Total
1. Word Form
thirty-four
Check for hyphen and correct spelling
2. Expanded Form
30 + 4
3 tens (30) + 4 ones (4)
3. Build-It (Base Ten) 3 Rods, 4 Cubes
| | |
• • • •
4. Tally Marks 6 bundles + 4 singles
|||| |||| |||| |||| |||| |||| ||||
MAT 2 KEY Clue: 50 + 6 = 56
4 Points Total
1. Standard Form
56
5 tens and 6 ones
2. Word Form
fifty-six
Watch spelling: "fifty"
3. Build-It (Base Ten) 5 Rods, 6 Cubes
| | | | |
• • • • • •
4. Tally Marks 11 bundles + 1 single
|||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |||| |
Quick Match Answer: Which tally count equals 25?
Correct: B (5 bundles of 5 = 25)
Double Digit Detectives • Answer Key Total Points: 9 Items Page 1 of 1
Form Hunter Station Cards Station Activity
Form Hunter Station Cards
Cut along dashed lines for 6 stations
STATION A Clue: Tally Marks
Count the tally bundles:
|||| |||| |||| |||| |||| |||| |||| |||
(7 bundles of 5, plus 3 singles)
Mission: Find standard & expanded form!
STATION B Clue: Base Ten
Inspect the visual model:
(4 rods of 10, 7 single units)
Mission: Find standard & word form!
STATION C Clue: Expanded
Decypher the equation:
60 + 5
(6 tens value + 5 ones value)
Mission: Find standard & tally bundles!
STATION D Clue: Word Form
Read the secret words:
eighty-two
(Listen to the tens and ones)
Mission: Find standard & expanded form!
STATION E Clue: Tally Marks
Count the tallies:
|||| |||| |||| |||| |||| ||||
(5 bundles of 5, plus 4 singles)
Mission: Find standard & word form!
STATION F Clue: Base Ten
Inspect the visual model:
(7 rods of 10, 1 single unit)
Mission: Find standard & expanded form!
Double Digit Detectives • Station Activity Set Card Cut-Outs: Stations A - F Page 1 of 2
Station Recording Log
Detective Mission Log
Agent Name:
Date:
Visit each station card, identify the mystery number, and record its representations in the log below!
Station
Standard
Expanded Form
Word Form
Tens & Ones
Station A
T, O
Station B
T, O
Station C
T, O
Station D
T, O
Station E
T, O
Station F
T, O
Mission Secret Code:
Add the ones digit of Station A (8) + Station C (5)
Ones from Station A + Ones from Station C =
Rank Unlocked: Master Detective!
Double Digit Detectives • Station Activity Set Student Mission Recording Sheet Page 2 of 2
Form Hunter Answer Key Teacher Station Guide & Key
Form Hunter Answer Key
Master Key
Station Setup Guide: Cut out the 6 station cards from page 1 and laminate them if possible. Place each card at a numbered table or wall station with dry-erase markers or concrete manipulatives (base-ten blocks and craft sticks for tallies).
Station Verification Solutions
Station
Standard
Expanded Form
Word Form
Tens & Ones
Station A
38
30 + 8
thirty-eight
3 T, 8 O
Station B
47
40 + 7
forty-seven
4 T, 7 O
Station C
65
60 + 5
sixty-five
6 T, 5 O
Station D
82
80 + 2
eighty-two
8 T, 2 O
Station E
29
20 + 9
twenty-nine
2 T, 9 O
Station F
71
70 + 1
seventy-one
7 T, 1 O
Secret Code Answer: Station A ones (8) + Station C ones (5) =
13
Differentiation & Support:
• Support: Provide physical base-ten blocks and popsicle sticks so students can rebuild Station A and E tally bundles hands-on.
• Extension: Have fast finishers pick any station number and write an addition story problem or draw what the number looks like on an open number line.
Double Digit Detectives • Teacher Key Station Set Scoring & Facilitation Guide Page 1 of 1
