Unit 1: Number Sense
Topic A: Place Value
Introduction to Place Values
Each place in a number has a value.
Ones
The ones place tells how many ones there are.
3 means 3 ones.
9 is the largest amount that we can express (write or say) with one digit.
Tens
The tens place shows how many tens there are. The ones place must have a digit in it before there can be a digit in the tens place.
Every ten is ten ones.
43 means 4 tens and 3 ones
99 means 9 tens and 9 ones. 99 is the largest amount that we can express (write or say) using only two digits.
Hundreds
The place to the left of the tens place is the hundreds place. It shows how many hundreds there are. A number written using three whole digits has a hundreds place, a tens place, and a ones place.
Every hundred is ten tens – every hundred is the same as one hundred ones.
Every hundred is ten tens – every hundred is the same as one hundred ones.
100 100 100
425 means 4 hundreds, 2 tens, and 5 ones.
Thousands
The place to the left of the hundreds place is the thousands place.
One thousand is the same as ten hundreds.
One thousand is the same as one hundred tens.
One thousand is the same as one thousand ones. (You will have to imagine the picture of the one thousand ones!)
Thousands Separator: Use a Space
When we write numerals, a little space is left between the thousands place and the hundreds place. The space makes it easier to read large numerals.
4392 8253 23693
Large numerals used to be written with a comma (,) instead of a space and you may still see numerals like this:
4,392 8,253 23,693
Learn to use the space instead of a comma because that is the preferred style.
Example A
2 212 means 2 thousands, 2 hundreds, 1 ten, and 2 ones
3 064 means 3 thousands, 0 hundreds, 6 tens, and 4 ones
What happens if the 0 is not written to hold the hundreds place? The numerals would then be 364 which stands for the number 3 hundreds, 6 tens, and 4 ones.
364 is not the same as 3 064.
Exercise One
Fill in the blanks to make each sentence true. Draw a sketch if you wish. Check your work using the answer key at the end of the exercise.
- 8261 = thousands hundreds tens ones
- 4005 = thousands hundreds tens ones
- 2931 = thousands hundreds tens ones
- 1034 = thousands hundreds tens ones
- 2608 = thousands hundreds tens ones
- 7543 = thousands hundreds tens ones
- 2900 = thousands hundreds tens ones
Answers to Exercise One
- 8 thousands 2 hundreds 6 tens 1 ones
- 4 thousands 0 hundreds 0 tens 5 ones
- 2 thousands 9 hundreds 3 tens 1 ones
- 1 thousands 0 hundreds 3 tens 4 ones
- 2 thousands 6 hundreds 0 tens 8 ones
- 7 thousands 5 hundreds 4 tens 3 ones
- 2 thousands 9 hundreds 0 tens 0 ones
Ten thousands
The place value to the left of thousands is ten thousands. As you can tell by the name, one ten thousand is ten thousands. You are not going to get a sketch of these large place values because the page isn’t big enough!
Example B
43692 = 4 ten thousands, 3 thousands, 6 hundreds, 9 tens, and 2 ones
43692 can also be thou