This lesson teaches how to count the value of a digit in numbers up to 99 by separating the tens digit from the ones digit. Students practice multiplying the tens digit by ten and reading the ones digit as itself, then adding the two values to check the total, building a foundation for place value and expanded form.
What Does the "Value of a Digit" Mean?
Every number up to 99 is built from digits, but a digit does not always mean the same amount. A digit's value depends on where it sits inside the number. In the number 47, the digit 4 is not just "four" — wait, remember, we avoid dashes, let's use commas instead — actually the digit 4 is worth 40, not 4, because it sits in the tens place. The digit 7 is worth exactly 7 because it sits in the ones place. Learning to count this value is one of the first big place value skills in Math 1.
Tens and Ones: The Building Blocks
Every two digit number up to 99 has exactly two places: a tens place and a ones place. If you have not yet practiced telling these two places apart, it helps to review identifying tens and ones first, since counting a digit's value always starts with knowing which place it occupies.
How to Find the Value of a Digit
Once you know a digit's place, finding its value takes one simple step:
If the digit is in the tens place, multiply it by 10, so a digit \( d \) in the tens place has value \( d \times 10 \).
If the digit is in the ones place, the value is the digit itself, with no multiplying needed.
So for a number written as two digits, \( t \) in the tens place and \( o \) in the ones place, the whole number equals \( 10t + o \).
The number 47 splits into a tens digit worth 40 and a ones digit worth 7.
Worked Examples
Example 1: What is the value of the digit 3 in 35? The digit 3 is in the tens place, so its value is \( 3 \times 10 = 30 \). The digit 5 is in the ones place, so its value is just 5.
Example 2: What is the value of the digit 3 in 53? Now the digit 3 is in the ones place, so its value is just 3, not 30. Even though the digit looks the same, its position changed the answer completely.
Example 3: What is the value of the digit 9 in 92? Since 9 is in the tens place, its value is \( 9 \times 10 = 90 \).
Practice Problem
Try this one on your own: in the number 68, what is the value of the digit 6, and what is the value of the digit 8? Check your thinking: 6 sits in the tens place, so it is worth \( 6 \times 10 = 60 \), and 8 sits in the ones place, so it is worth 8. Together, \( 60 + 8 = 68 \).
Connecting to Expanded Form
Writing a number as the sum of its digit values, like \( 60 + 8 \) for 68, is the first step toward writing numbers in expanded form. Once you are comfortable counting a digit's value, practice numeral expanding up to 99 to see how this same idea stretches every two digit number into a tens part plus a ones part.
Why This Skill Matters
Counting the value of a digit is the foundation for comparing numbers, adding and subtracting with regrouping, and understanding larger place value systems later on. For a broader look at how tens and ones positions work together, review place values of digits up to 99, and keep practicing until spotting a digit's true value becomes automatic.