- Position Rule: Tens digit goes in the tens place (second from right)
- Value Rule: Each ten represents 10 ones
- Standard Form: Write using digits only
Standard form: Writing a number using digits (e.g., 15)
Place value: The value of a digit depends on its position in the number
Note: In grade 1, we focus on tens and ones. Each ten represents 10 ones.
- Count the tens: 1 ten = 10
- Count the ones: 5 ones = 5
- Add tens and ones together: 10 + 5 = 15
1 ten = 1 × 10 = 10
5 ones = 5 × 1 = 5
10 + 5 = 15
The standard form of 1 ten and 5 ones is 15
• Place value: Tens place represents groups of 10
• Standard form: Write number using digits
• Addition: Combine tens and ones values
• Practice Tip: Use base ten blocks to visualize: 1 long rod (ten) and 5 small cubes (ones)
- 2 tens and 3 ones = 23
- 1 ten and 9 ones = 19
- 4 tens and 0 ones = 40
- Each ten is worth 10 ones
- The tens digit goes in the tens place (second from right)
- The ones digit goes in the ones place (rightmost)
Q: What if I have more than 9 ones?
A: Regroup 10 ones as 1 ten. For example, 1 ten and 13 ones = 2 tens and 3 ones = 23.
Q: How do I write 0 tens and 7 ones?
A: That's just 7 ones = 7. We don't usually write 07, just 7.
- Position Rule: Left digit is tens, right digit is ones
- Value Rule: Tens digit × 10 + ones digit × 1
- Decomposition Rule: Break number into place values
Digit analysis: Breaking down a number to identify tens and ones
Note: In any two-digit number, the left digit is tens and the right digit is ones.
- Identify the tens digit: leftmost digit
- Identify the ones digit: rightmost digit
- State the number as tens and ones
In 34, the tens digit is 3
In 34, the ones digit is 4
34 = 3 tens and 4 ones
34 represents 3 tens and 4 ones
• Position rule: Left digit is tens, right digit is ones
• Value rule: Tens digit × 10 + ones digit
• Representation: Show as groups of tens and ones
• Practice Tip: Count by tens: 10, 20, 30, then add ones: 31, 32, 33, 34
- 42 = 4 tens and 2 ones
- 78 = 7 tens and 8 ones
- 60 = 6 tens and 0 ones
- Always read from left to right: tens first, then ones
- 34 means 3 groups of 10 and 4 individual units
- Count by tens first, then count ones
Q: What if the number is less than 10?
A: Single-digit numbers have 0 tens and the number as ones. For example, 6 = 0 tens and 6 ones.
Q: How do I know which digit is tens?
A: In a two-digit number, the left digit is always the tens place.
- Block Value Rule: Each tens block = 10 ones blocks
- Counting Rule: Count tens and ones separately
- Combination Rule: Add tens and ones values
Base ten blocks: Visual tools representing tens (long rods) and ones (small cubes)
Note: Each tens block equals 10 ones blocks. This helps visualize place value.
- Count the tens blocks and multiply by 10
- Count the ones blocks
- Add the values together
2 tens blocks = 2 × 10 = 20
7 ones blocks = 7 × 1 = 7
20 + 7 = 27
The standard form is 27
• Base ten concept: Each tens block equals 10 ones
• Counting: Separate tens and ones before adding
• Standard form: Write total as a number
• Practice Tip: Draw the blocks to visualize: 2 long rectangles and 7 small squares
- 3 tens and 4 ones blocks = 34
- 5 tens and 0 ones blocks = 50
- 1 ten and 9 ones blocks = 19
- Each tens block is worth 10 individual units
- Count tens first, then add ones
- Visual representation helps understand place value
Q: Can I trade 10 ones blocks for 1 tens block?
A: Yes! This is called regrouping. 10 ones = 1 ten.
Q: What if I have 10 tens blocks?
A: 10 tens = 1 hundred. In grade 1, we focus on tens and ones.
- Decomposition Rule: Break number into place values
- Value Rule: Tens digit × 10 + ones digit × 1
- Expression Rule: Show value of each digit separately
Expanded form: Writing a number showing the value of each digit (e.g., 46 = 40 + 6)
Note: This shows the actual value each digit contributes to the whole number.
- Identify the tens digit and its value
- Identify the ones digit and its value
- Write as a sum of these values
4 in the tens place = 4 × 10 = 40
6 in the ones place = 6 × 1 = 6
46 = 40 + 6
46 in expanded form is 40 + 6
• Place value: Each position has a specific value
• Expanded form: Shows value of each digit separately
• Standard form: The usual way to write numbers
• Practice Tip: Expanded form helps understand what each digit represents
- 35 = 30 + 5
- 82 = 80 + 2
- 40 = 40 + 0
- Expanded form shows the actual value of each digit
- Tens digit × 10 + ones digit × 1
- This connects to standard form: 40 + 6 = 46
Q: Why do we learn expanded form?
A: It helps understand place value and makes addition/subtraction easier.
Q: Can I write expanded form for single digits?
A: Yes! For example, 7 = 0 + 7 or just 7.
- Position Rule: Left digit is tens, right digit is ones
- Organization Rule: Chart organizes by place value
- Value Rule: Digit × place value
Place value chart: Organizes digits by their place (tens, ones)
Note: Charts help organize thinking about place value and make it easier to understand.
- Identify the tens digit
- Identify the ones digit
- Fill the chart accordingly
In 58, the tens digit is 5
In 58, the ones digit is 8
Tens: 5, Ones: 8, Total: 58
Tens: 5, Ones: 8, Standard Form: 58
• Organization: Charts help organize place value thinking
• Position rule: Left digit is tens, right digit is ones
• Value calculation: Digit × place value
• Practice Tip: Use charts to double-check your work
- For 46: Tens=4, Ones=6
- For 80: Tens=8, Ones=0
- For 27: Tens=2, Ones=7
- Charts help organize thinking about place value
- Always fill tens first, then ones
- Check that your chart adds up to the original number
Q: Do I need to use a chart for every problem?
A: Not always, but charts are helpful when learning or checking work.
Q: What if I have more than two digits?
A: Grade 1 focuses on tens and ones. Later grades add hundreds, thousands, etc.