Base ten blocks: Physical or visual manipulatives that represent different place values
Note: In grade 1, we focus on cubes (ones) and rods (tens).
- Identify the cube: represents 1 unit (one)
- Identify the rod: represents 10 units (ten)
- Recognize how blocks relate to each other (10 cubes = 1 rod)
A small cube represents 1 unit (one)
A long rod represents 10 units (ten)
10 cubes can be grouped together to make 1 rod
Cubes represent ones (1), rods represent tens (10)
• One-to-one correspondence: Each cube represents one unit
• Grouping principle: 10 ones make 1 ten
• Visual representation: Rods show the value of ten units
• Practice Tip: Count 10 cubes to verify they equal one rod
- 1 cube = 1 one - Practice with single units
- 1 rod = 10 ones - Practice with tens
- 2 rods = 20 ones - Practice with multiple tens
- Cubes are small and represent single units
- Rods are long and represent groups of 10
- 10 cubes lined up equal the length of 1 rod
Q: Why do we use base ten blocks?
A: Base ten blocks help visualize numbers and understand place value by showing groups of 10.
Q: Are there other types of base ten blocks?
A: Yes, there are flats (100) and large cubes (1000), but in grade 1 we focus on cubes and rods.
Number representation: Using base ten blocks to show the place value of a number
Note: Identify how many tens and ones are in the number.
- Identify the tens digit in the number
- Use rods to represent the tens
- Identify the ones digit in the number
- Use cubes to represent the ones
24 = 2 tens + 4 ones
2 tens = 2 rods
4 ones = 4 cubes
2 rods + 4 cubes = 24
2 rods and 4 cubes
• Place value breakdown: Separate tens and ones
• Block assignment: Rods for tens, cubes for ones
• Visual verification: Count blocks to confirm total
• Practice Tip: Use physical blocks to manipulate and verify
- 35 = 3 rods + 5 cubes - Practice with different numbers
- 18 = 1 rod + 8 cubes - Practice with smaller tens digit
- 42 = 4 rods + 2 cubes - Practice with different combinations
- Always start by identifying tens and ones
- Rods represent the tens digit
- Cubes represent the ones digit
Q: How do I know how many rods to use?
A: The tens digit tells you how many rods to use. For 24, the tens digit is 2, so use 2 rods.
Q: Can I use only cubes to represent 24?
A: Yes, you could use 24 individual cubes, but using 2 rods and 4 cubes is more efficient.
Number comparison: Using base ten blocks to visually compare the value of numbers
Note: Compare the number of rods first, then cubes if needed.
- Represent each number with base ten blocks
- Compare the number of rods (tens)
- If tens are equal, compare the number of cubes (ones)
- Determine which number is greater based on the comparison
32 = 3 rods + 2 cubes; 27 = 2 rods + 7 cubes
32 has 3 rods, 27 has 2 rods. Since 3 > 2, 32 > 27
32 is greater than 27 because it has more tens
32 is greater than 27 because 32 has 3 rods while 27 has only 2 rods
• Visual comparison: Blocks make it easier to see which number is larger
• Start with tens: Compare rods first, then cubes if needed
• Systematic approach: Always compare from highest place value down
• Practice Tip: Build both numbers with blocks to see the difference
- 45 vs 38 → 45 > 38 (4 rods > 3 rods)
- 51 vs 58 → 58 > 51 (equal rods, 8 cubes > 1 cube)
- 39 vs 42 → 42 > 39 (4 rods > 3 rods)
- Build both numbers with blocks to compare visually
- Always start comparing from the rods (tens)
- More rods always means a greater number
Q: What if both numbers have the same number of rods?
A: Then compare the number of cubes. The number with more cubes is greater.
Q: Why do we start comparing with rods?
A: Because rods represent tens, which have greater value than ones.
Building numbers: Constructing a number using the appropriate base ten blocks
Note: Identify tens and ones, then use corresponding blocks.
- Identify the tens digit (4 in 46)
- Use that many rods (4 rods)
- Identify the ones digit (6 in 46)
- Use that many cubes (6 cubes)
46 = 4 tens + 6 ones
4 tens = 4 rods
6 ones = 6 cubes
4 rods + 6 cubes = 46
4 rods and 6 cubes
• Place value identification: Recognize tens and ones digits
• Block assignment: Match rods to tens, cubes to ones
• Construction process: Build the number systematically
• Practice Tip: Count the total to verify the number is correct
- Build 35: 3 rods + 5 cubes
- Build 58: 5 rods + 8 cubes
- Build 21: 2 rods + 1 cube
- Always start with the tens (rods) then add ones (cubes)
- Line up rods together and cubes together
- Count the total to verify you built the correct number
Q: Can I build a number in a different way?
A: You can use all cubes, but using the correct combination of rods and cubes is more efficient.
Q: How do I know if I built the number correctly?
A: Count the total value of your blocks to verify it matches the target number.
Place value interpretation: Determining the number represented by given base ten blocks
Note: Each rod represents 10, each cube represents 1.
- Count the number of rods (tens)
- Multiply by 10 to get the tens value
- Count the number of cubes (ones)
- Add the tens and ones values together
3 rods = 3 × 10 = 30
7 cubes = 7 × 1 = 7
30 + 7 = 37
37
• Rod value: Each rod represents 10 units
• Cube value: Each cube represents 1 unit
• Place value addition: Tens + ones = the total number
• Practice Tip: Count by tens for rods, then count on for cubes
- 2 rods + 5 cubes = 25
- 4 rods + 3 cubes = 43
- 1 rod + 9 cubes = 19
- Rods represent tens (multiply by 10)
- Cubes represent ones (count as single units)
- Add the tens and ones values together
Q: How do I calculate the value of rods?
A: Each rod represents 10, so multiply the number of rods by 10.
Q: What if I have more than 10 cubes?
A: 10 cubes can be traded for 1 rod. So 13 cubes would be 1 rod and 3 cubes.