Expanded Form

About this activity

Children build a three-digit number out of base-ten blocks — tapping in hundreds-flats, ten-rods, and unit-cubes — and when the build is right the blocks reveal the expanded form, so 247 becomes 200 + 40 + 7, with targets from 108 up to 974 including tricky numbers like 305. It's a free, interactive Grade 2 math activity that runs right in the browser with no account.

The big idea is that a number is the sum of what each digit is worth. By building 247 from two hundreds, four tens, and seven ones, the child sees that the 4 means 40, not just 'four.' Numbers with a zero are the key teachers: 305 shows that an empty tens place adds nothing, so the expanded form is just 300 + 5. The blocks connect the digits to their real value.

It is aligned to Common Core 2.NBT.A.3 — reading and writing three-digit numbers in expanded form. No timer, no score — just calm, playful practice.

What's inside this activity

• Designed for Grade 2 learners (ages about 7–8)
• Common Core strand: Number & Operations in Base Ten
• Aligned to Common Core standard 2.NBT.A.3

How to play

Tap to add hundreds-flats, ten-rods, and unit-cubes until you build the target number.

When the build is right, the blocks reveal the expanded form, like 200 + 40 + 7.

Move on to the next number; there is no timer and no score.

What your child practices

• Build a three-digit number from hundreds, tens, and ones
• Read the number in expanded form, like 247 = 200 + 40 + 7
• See that each digit's value depends on its place
• Handle numbers with a zero place, like 305 = 300 + 5

Learning goals

Read and write three-digit numbers in expanded form — the focus of Common Core 2.NBT.A.3

Understand that a number is the sum of its place values

Build the place-value sense that supports adding and comparing numbers