Tuck Breaks a Hundred — Subtract with Regrouping (Grade 2)

About this activity

Tuck the hamster shows base-ten blocks for the hardest kind of borrowing — subtracting from a three-digit number with no tens to borrow from, like 302 − 5 and 201 − 6 — so children tap 'Break a hundred' for ten ten-rods, then 'Break a ten' for ten ones, take some away, and type the answer. It's an interactive Grade 2 math activity that runs right in the browser with no account.

The big idea is borrowing across a zero, which trips up many children because the tens place is empty. Seeing the blocks makes it sensible: you cannot break a ten that is not there, so you first break a hundred into ten tens, and THEN break a ten into ten ones. The two-step trade is something the child performs and watches, not a rule to memorize, so 'borrowing across zero' finally makes physical sense.

It is aligned to Common Core 2.NBT.B.7 — subtracting within 1000 using concrete models and understanding that you sometimes decompose a hundred and a ten. 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 subtraction, like 302 − 5, and watch Tuck show the blocks.

Tap 'Break a hundred' for ten tens, then 'Break a ten' for ten ones, and take some away.

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

What your child practices

• Subtract from a three-digit number that has a zero in the tens place
• Break one hundred-flat into ten ten-rods
• Then break one ten-rod into ten ones to take ones away
• Understand borrowing across zero as decomposing a hundred, then a ten

Learning goals

Subtract within 1000 with regrouping across zero — the focus of Common Core 2.NBT.B.7

Understand that one hundred decomposes into ten tens, and one ten into ten ones

Build the place-value reasoning behind written subtraction with borrowing