Place value explained with blocks: hundreds, tens and ones

For: Ages 6-9, parents and teachers. Updated 2026-10-15.

Our number system only uses ten digits, 0 to 9. It can still write any number because the position of a digit decides what it is worth. That idea is called place value, and it is the foundation for adding, subtracting and everything after.

One block, one column, one flat

Base-ten blocks make place value visible. A single cube is one. Ten cubes joined in a column make a ten. Ten columns side by side make a flat square of one hundred. Ten flats stacked make a cube of one thousand. Each step is exactly ten times the one before, which is why we call it base ten.

Read the table from top to bottom and you have the expanded form: 347 = 300 + 40 + 7.

The job of zero

In 405 there are no tens, but we still write the 0. Without it the 4 would slide into the tens place and the number would read 45. When a child writes "4005" for four hundred and five, they are writing what they hear: four hundred, then five. Building the number with blocks and then writing one digit per column usually fixes this faster than repeating the rule.

Common mix-ups and what to try

• Reversing teen numbers (writing 71 for 17). Say "one ten and seven ones" while placing the blocks.
• Thinking a bigger digit always means a bigger number, so 89 looks bigger than 102. Compare the hundreds first: 102 has one flat, 89 has none.
• Counting a ten column as one thing and forgetting it is worth ten. Ask the child to count the cubes inside a column once, slowly.

Type 405 into the Number Blocks Tool and look at the tens row in the place-value table. Open the tool with 405

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