Digits
Grade 4 students learn about digits in Saxon Math Intermediate 4 Chapter 1, understanding that all numbers are built from just ten digit symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. Like letters of an alphabet, these ten digits combine to form any number imaginable. Students count how many digits a number contains, identify specific digit positions, and find the units digit (last digit) using a shortcut—only the units digits of factors are needed to find the units digit of a product: 13 × 17 has units digit 3 × 7 = 21, so the units digit is 1.
Key Concepts
Property Digits are the ten numerals we use to write all numbers: $0, 1, 2, 3, 4, 5, 6, 7, 8, 9$.
Examples The number $64,000$ is built using five different digits. In the number $5281$, the very last digit is $1$.
Explanation Digits are the basic building blocks for every number you can imagine, just like letters are for the alphabet! We can use them to count how many digits are in a huge number or find the very last one, which is super handy.
Common Questions
What are digits?
Digits are the ten symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) used to write every number. Just as letters combine to form words, digits combine in different positions to form all possible numbers.
What is the units digit of a number?
The units digit (also called the last digit) is the digit in the ones place—the rightmost digit of the number. For 1,327, the units digit is 7. For 5281, the units digit is 1.
What is a shortcut to find the units digit of a product?
Multiply only the units digits of the factors. The units digit of that product is the units digit of the full product. For 13 × 17: units digits are 3 and 7; 3 × 7 = 21; units digit of the product is 1.
How many digits does a five-digit number have?
Exactly five digits. A five-digit number uses all five place-value positions: ten-thousands, thousands, hundreds, tens, and ones—with one digit in each position.
How is a digit different from a number?
A single digit is always 0 through 9. A number can have any count of digits. The digit 3 is a single symbol, but 347 is a three-digit number formed by combining three digits.
Why does place value matter even though the same digit can appear multiple times?
The same digit represents a different value depending on its position. In 555, the first 5 (hundreds place) is worth 500, the second 5 (tens place) is worth 50, and the third 5 (ones place) is worth 5.