| digit | One of the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. |
| expanded form | A way to write a number as a sum of the value of its digits. For example, thirty-two is written in expanded form as 30 + 2, or 3 tens + 2 ones, or (3 • 10) + (2 • 1). |
| period | Each group of three digits in a number separated by a comma. |
| place value | The value of a digit based on its position within a number. |
| place-value chart | A chart that shows the value of each digit in a number. |
| standard form | A way to write a number using digits. For example, thirty-two is written in standard form as 32. |
| whole number | Any of the numbers 0, 1, 2, 3, and so on. |