Five-digit numbers

1Summary 重點摘要

10000 is ten thousand. 5 digits: ten-thousands, thousands, hundreds, tens, ones.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Part 1: Five digits, five placesTake 24531. From the right: ones 1, tens 3, hundreds 5, thousands 4, ten-thousands 2. Each digit sits in its own place with its own value. Read from the left: twenty-four thousand, five hundred thirty-one. When writing a number, also start from the highest place and never miss a place, so every digit lands in its proper seat.
2. Part 2: How big is ten thousand?9999 plus 1 makes 10000, so ten thousand is only one more than the largest four-digit number. Ten one-thousands make one ten-thousand. If one lap of the track is 400 m, then 25 laps is 10000 m — that shows how far it is. Ten thousand is also the start of the new counting unit 'ten-thousand', the springboard for every larger number to come.
3. Part 3: Expanded formWrite 24531 as 20000 + 4000 + 500 + 30 + 1. The 2 in the ten-thousands place means 20000, the 4 in the thousands place means 4000, and so on for the hundreds, tens and ones. Expanded form shows what every digit is really worth. Mastering it helps both with place value and with comparing sizes, and keeps the places straight in exercises.
4. Part 4: Zeros in the middle20405 reads twenty thousand four hundred and five. Both middle zeros must be written and read; leaving one out changes the number. Miss the thousands 0 and 20405 wrongly becomes 2405, a completely different value. When several zeros stand side by side in the middle, only one 'zero' is read, but in writing each 0 must still hold its own place.
5. Part 5: Comparing five-digit numbersCompare 45678 and 45768: the ten-thousands tie at 4, the thousands tie at 5, then at the hundreds 6 is less than 7, so 45678 < 45768. Always compare from the left, place by place; the first place that differs decides the result. Two numbers with different digit counts: the one with more digits is larger and can be judged at once.
6. Part 6: Place value in actionIn 36728 the digit 6 sits in the thousands place, so it means 6 thousands, or 6000. The same 6 in the ten-thousands place would mean 60000. The same digit means different amounts in different places — that is exactly what place value means. In exercises, first confirm which digit and which place the question asks about, then write the value it stands for, and the answer stays on target.

4Diagrams Diagrams

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• Five places: ten-thousands, thousands, hundreds, tens, ones, from the right
• 10 thousands = one ten-thousand (10000)
• 24531 = 20000 + 4000 + 500 + 30 + 1
• Write and read middle zeros: 20405 reads twenty thousand four hundred and five
• Compare five-digit numbers from the ten-thousands place