Add within 100 with Regrouping

Students add two numbers within 100 when the ones digits sum to 10 or more, regrouping ten ones into a new ten (e.g., 47 + 35 = 82).

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Grade 2 · Fluent Addition and Subtraction within 100 · question 1 of 3

0 of 12

12 rungs. A star at the top.

19 + 22 =

How it is taught

0:00 of 3:26

Add ones, then tens.

Ten ones make one ten.

Read it: Trade ones for a ten

You have 17 cubes. Fifteen more arrive. Counting every cube from one is slow — look at the loose ones, and the ring of ten.

Add the ones: 7 and 5 make 12.
Trade ten ones for a new ten. Two stay.
Add the three tens and the 2 ones: 32.

Counting all 17 plus 15 from one works, but it is slow and easy to lose track.

Ones can make more than 9, so you trade ten of them for a ten you can carry.

After the trade, 12 ones become 1 ten and 2 ones, so the tens are ready to add.

Add the ones, trade ten of them for a ten, then add the tens.

Writing 12 in the ones place and forgetting to trade ten for a ten.

12 ones are a ten and 2 ones. Trade the ten, then add it with the other tens.

18 + 13 = ___ — 31. Add the ones: 8 + 3 = 11. Trade 10 of them for a ten, then add the tens.

47 + 35

Let's add forty-seven plus thirty-five.

We stack them in columns — ones with ones, tens with tens.

Start with the ones column. What is seven plus five?

Twelve! But twelve is too big to fit in one place. We have to regroup.

Twelve is one ten and two ones. Write the two in the ones place.

Now carry the one ten up to the top of the tens column.

Now add the tens. One plus four plus three.

That makes eight tens.

Write eight in the tens place.

Grade 2 · Adding two-digit numbers with regrouping

Forty-seven plus thirty-five is eighty-two. Nice regrouping!

What you see

While they climb, your page writes one true line to ask about tonight, and a short note each Sunday.

MayaGrade 3 · Mathematics

Did you know?

A chessboard has 64 squares — share them out between the 8 rows and each row holds exactly 8.

Today’s goal: 1 star — one skill mastered, every rung of its ladder climbed
Climbing now: Divide within 100

An example student.

MayaGrade 3 · Mathematics

Maya earned 2 stars this week — Interpret multiplication as equal groups, which took 6 answers over 3 days before its star landed 3 days ago and Multiply by 6, 7, 8 and 9. Next up: Divide within 100.

An example week.

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