1
Hundreds, tens and ones
Discover Mathematics P2: Term 1, Lessons 21–30
GoalRead and write three-digit numbers using hundreds, tens and ones.
New words
hundreds · big squares: one hundred eachtens · rods: ten eachones · small cubes: one eachdigit · one of the symbols 0 to 9
Explanation
A number with three digits has hundreds, tens and ones. Ten ones make one ten, and ten tens make one hundred. In 385 the first digit is 3, so there are 3 hundreds. The second digit is 8, so there are 8 tens. The last digit is 5, so there are 5 ones. 300 + 80 + 5 = 385. A zero means there are none of that place.
Worked examples
Look at the blocks: 2 hundreds, 4 tens and 3 ones. The number is 243.
407 has 4 hundreds, 0 tens and 7 ones. The zero shows that there are no tens.
Ten tens make one hundred. So 10 rods can be swapped for 1 big square.
Class activity
Build numbers at home. Use 20 small things for ones, such as beans, and make groups of ten with a rubber band. Show 2 groups of ten and 6 ones. Say the number, 26. Then try 3 tens and 4 ones.
Practice
1
Which number do the blocks show?
234
2
How many hundreds, tens and ones are in 306?
3 hundreds, 0 tens, 6 ones
3
Write the number: 5 hundreds, 1 ten and 9 ones.
519
4
What is the tens digit of 472?
7
5
How many tens make 100?
10