Learn
Digit and number
Digits are the symbols 0 through 9. We use them to write numbers. The number 482 has three digits. Here 4 is worth 400, 8 is worth 80, and 2 is worth 2.
Ten smaller units make one larger unit
Ten ones make one ten. Ten tens make one hundred. Ten hundreds make one thousand. Each place to the left is worth ten times the adjacent place to its right.
Zero holds a place
Read 607 as six hundred and seven. Zero says there are no tens. If we leave it out, we get 67, a different number. The number 1,000 is one thousand and has four digits.
Worked examples
482 = 400 + 80 + 2
Read: four hundred and eighty-two. Each part shows one digit’s place value.
607 = 6 × 100 + 0 × 10 + 7
Six hundreds, zero tens, and seven ones. Keep zero in the written number 607.
Try it yourself
Your turn
Type the missing word, number, or sign. Spaces in large numbers are allowed. Try first, then open the explanation.
Write two three-digit numbers with digits 2, 0, and 8. Explain why a three-digit number does not start with zero.
See an example answer
Examples: 208 and 820. The notation 028 represents 28, which has two digits in its usual form.
Check your knowledge
Choose one answer for each question. You can revise your answers and check again.
Answer key
- 806. Zero holds the tens place.
- 400. Four hundreds are worth 400.
- 300 + 50 + 9. Each part keeps its correct place value.
- 4. It contains a one and three zeros.
- 721. 700 + 20 + 1 = 721.