Same Math › Grades 1–2 › Base-ten blocks
What are base-ten blocks?
Base-ten blocks are cubes, rods and flats that stand for ones, tens and hundreds. Kids use them to see what a number is made of, and to understand regrouping before they do it on paper.
- A flat is 100: ten rods side by side.
- A rod is 10: ten cubes in a stick. A single cube is 1.
- 2 hundreds + 4 tens + 3 ones = 243
Why schools teach it
They make "carrying" make sense
With blocks, kids can see that the 4 in 243 is four tens, not four. First graders are expected to understand a two-digit number as tens and ones (1.NBT.B.2), and blocks are the usual way to show it.
Blocks also explain regrouping. With 10 cubes, you trade them for 1 rod. That trade is what "carrying" really is, which is why your child's class may say regroup or trade instead.
At the kitchen table
What to say, and what to skip
Say this
How many tens do you see? How many ones?
We have 12 cubes. Can we trade some for a rod?
Trading 10 cubes for a rod is regrouping.Can you build 243 a different way?
1 flat, 14 rods and 3 cubes is also 243. Teachers love this question.- Use the class words: trade, regroup.Same idea as carrying, but it says what actually happens.
Skip this
Carry the one.
Classes now say regroup or trade, because it describes what happens.- Counting every cube one by one.Count the flats by 100s, the rods by 10s, then the cubes. That is the skill.
Blocks are for little kids.
Classes use them through 5th grade, including for decimals.
See it in action
Using blocks for 156 − 38
Build 156: 1 flat, 5 rods, 6 cubes
There aren't 8 cubes to take away, so trade a rod for 10 cubes
1 hundred, 4 tens, 16 onesTake away 3 rods and 8 cubes
1 hundred, 1 ten, 8 ones = 118
That trade in step 2 is the "borrow" from the method we learned. Blocks show why it works.
Free practice sheet
Make a base-ten blocks sheet
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Parents also ask
We don't have blocks at home. What can we use?
Drawings work: squares, sticks and dots. Coins work too: dimes for tens and pennies for ones.
Why can my child build 243 with 14 rods?
Because 14 tens is the same as 1 hundred and 4 tens. Showing a number in more than one way is a 2nd-grade skill.
What's the big cube for?
Some sets include a large cube for 1,000 (ten flats stacked).
Are blocks used with decimals?
Yes, in grades 4 and 5. The flat can stand for 1 whole, so a rod is 0.1 and a cube is 0.01.