Now you can build any number up to 999 with three kinds of blocks: hundreds (flats), tens (rods) and ones (small cubes). It works just like Tens and Ones, with one more place.
Why it works
Each place holds only 0 to 9 of something, because 10 of anything gets bundled into the next place. So a three-digit number has exactly one digit for hundreds, one for tens and one for ones. The place of a digit tells what it is worth: in 352, the 3 is worth 300, the 5 is worth 50 and the 2 is worth 2.
Worked example: Read the blocks
What number is 2 hundreds, 4 tens and 7 ones?
- 2 hundreds is 200.
- 4 tens is 40.
- 7 ones is 7.
- Write one digit in each place: 247.
Answer: 247
Worked example: A zero holds a place
What number is 3 hundreds and 4 ones?
- Hundreds: 3.
- There are no tens, so write 0 in the tens place to hold it.
- Ones: 4. The number is 304.
Answer: 304
Worked example: What is a digit worth?
What is the 6 worth in 563?
- The 6 is in the tens place.
- 6 tens is 60.
Answer: 60
Key idea
In a three-digit number, the digits stand for hundreds, tens and ones, from left to right. A 0 holds a place when there are none of that kind.
Common mistake
Writing 3 hundreds and 4 ones as 34 or 3004. But 34 means 3 tens and 4 ones, and 3004 is more than three thousand. Check: a number in the hundreds has exactly three digits, and the middle one tells the tens.
Grown-up tip: Read numbers on house doors, book pages or price tags together, and ask what each digit is worth.