Tuck Makes a Hundred — Add with Regrouping (Grade 2)

About this activity

Tuck the hamster shows base-ten blocks while children add tens that pile up past ten tens — sums like 160 + 50, 280 + 30, and 410 + 90 — tapping 'Make a hundred' to bundle ten ten-rods into a single hundred-flat, then typing the total. It's a free, interactive Grade 2 math activity that runs right in the browser with no account.

The big idea is what carrying really means: ten tens are exactly one hundred. Instead of memorizing a written carry, the child sees the ten ten-rods clump together and become a hundred-flat, so 'regrouping into the hundreds' becomes a thing they can watch happen. The blocks make the abstract step concrete before the number is ever written down.

It is aligned to Common Core 2.NBT.B.7 — adding within 1000, using concrete models, and understanding that you sometimes compose a hundred. 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.B.7

How to play

Read the addition and watch Tuck show the tens as base-ten blocks.

Tap 'Make a hundred' to bundle ten ten-rods into one hundred-flat.

Type the total on the keypad; try again any time, with no timer and no score.

What your child practices

• Add multiples of ten that cross into a new hundred, like 340 + 70
• Bundle ten ten-rods into one hundred-flat
• Understand carrying as composing a hundred from ten tens
• Type the correct total after regrouping

Learning goals

Add within 1000 with regrouping into the hundreds — the focus of Common Core 2.NBT.B.7

Understand that ten tens compose one hundred

Build place-value understanding that supports written addition