Ten little ones. One mighty ten.

SparkClass

Combine base-ten blocks, spot a group of ten ones, and trade it for a brand-new ten rod.

CCSS 2.NBT.B.5 · B.9
Live Place-Value Chart
47+38
01

Meet the addends. 47 has 4 tens and 7 ones. 38 has 3 tens and 8 ones.

Tens7
+
Ones15
=
Total85

From blocks to written arithmetic

Keep the quantity visible while students connect each action to the recording.

1

Combine before trading

At 47 + 38, students first see 7 tens and 15 ones. The sum is already 85; regrouping simply records that same quantity in standard form.

2

Make the ten one object

Pause at the highlighted ones. Count all ten, then watch them move into the segments of one rod. The carried 1 names that rod: 1 ten.

3

Test the boundary

Use 36 + 22. With only 8 ones, there is nothing to trade. The lab explicitly says “No new ten needed” and leaves the ones untouched.

CCSS alignment: 2.NBT.B.5 supports fluent two-digit addition using place-value strategies; 2.NBT.B.9 asks students to explain why the strategy works. The block model makes the regrouping rationale visible.