Standard form: Writing a number using digits (e.g., 25)
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: 2 tens = 20
- Count the ones: 5 ones = 5
- Add tens and ones together: 20 + 5 = 25
2 tens = 2 × 10 = 20
5 ones = 5 × 1 = 5
20 + 5 = 25
The standard form of 2 tens and 5 ones is 25
• 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: 2 long rods (tens) and 5 small cubes (ones)
- 3 tens and 4 ones = 34
- 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, 2 tens and 13 ones = 3 tens and 3 ones = 33.
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.
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 48, the tens digit is 4
In 48, the ones digit is 8
48 = 4 tens and 8 ones
48 represents 4 tens and 8 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, 40, then add ones: 41, 42, 43, 44, 45, 46, 47, 48
- 23 = 2 tens and 3 ones
- 89 = 8 tens and 9 ones
- 40 = 4 tens and 0 ones
- Always read from left to right: tens first, then ones
- 48 means 4 groups of 10 and 8 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.
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
3 tens blocks = 3 × 10 = 30
7 ones blocks = 7 × 1 = 7
30 + 7 = 37
The standard form is 37
• 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: 3 long rectangles and 7 small squares
- 2 tens and 3 ones blocks = 23
- 5 tens and 0 ones blocks = 50
- 1 ten and 8 ones blocks = 18
- 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.
Expanded form: Writing a number showing the value of each digit (e.g., 56 = 50 + 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
5 in the tens place = 5 × 10 = 50
6 in the ones place = 6 × 1 = 6
56 = 50 + 6
56 in expanded form is 50 + 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
- 25 = 20 + 5
- 73 = 70 + 3
- 40 = 40 + 0
- Expanded form shows the actual value of each digit
- Tens digit × 10 + ones digit × 1
- This connects to standard form: 50 + 6 = 56
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.
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 83, the tens digit is 8
In 83, the ones digit is 3
Tens: 8, Ones: 3, Total: 83
Tens: 8, Ones: 3, Standard Form: 83
• 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 34: Tens=3, Ones=4
- For 80: Tens=8, Ones=0
- For 17: Tens=1, 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.