The multiples of 10
Understand that the multiples of 10 (10, 20, 30 … 90) represent one to nine tens and 0 ones
What a learner can do afterwards
- Explain that 30 means 3 tens and 0 ones
- Represent 50 using 5 tens rods and no unit cubes
- Match decade numbers to their tens representation
1 · Read
You already know that a ten is ten ones bundled together. Now count using only whole tens: 10, 20, 30, 40, 50, 60, 70, 80, and 90. Each of these numbers is built from tens alone, with nothing extra left over as loose ones.
Mia lines up 5 tens rods and no loose cubes. She counts 10, 20, 30, 40, 50. That number, 50, means 5 tens and 0 ones.
Look at the ones place in 30, 50, or 90. It always shows a zero. That zero is a placeholder. It means there are no loose ones, only whole tens.
Every multiple of ten is made only of whole tens, and the zero in the ones place shows nothing is left over.
More to read
Tens and Ones
Decade numbers are pure tens with empty ones pockets. Thirty means 3 full tens and 0 ones, which is why it ends in zero. Fifty lines up 5 ten rods with no cubes beside them. Read any multiple of 10 by naming its tens pile first, then adding the zero pocket.
Adding and Subtracting Within 100 Using Place Value Strategies (Grade 2)
Counting by tens climbs the decades ladder: 10, 20, 30, all the way to 100. Each rung adds one more tens rod and keeps the ones at zero. Clap once per rung so the rhythm locks the pattern in. Once the ladder is smooth, start it mid-way at 40 and climb to 90.
1.4 Multiply Whole Numbers
Matching decades to tens is a pairing game. Eighty shakes hands with 8 tens, sixty with 6 tens. Lay the rods out, count the piles, and pin the right numeral beside each row. When every numeral holds hands with its pile, the whole tens family stands in order.
Explore more
2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
Optional connections
This opens up
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
17 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.