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Add within 100 without Regrouping

Students add two numbers within 100 when the ones digits sum to 9 or less, so no regrouping is required (e.g., 42 + 35 = 77).

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Add within 100 without Regrouping

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

0 of 12

12 rungs. A star at the top.

+ 10 = 22

How it is taught

0:00 of 3:33

When ones add to nine or less, you do not regroup.

Keep tens with tens and ones with ones.

Read it: Tens with tens, ones with ones

61 + 21: 61 is 6 tens and 1 one, and 21 is 2 tens and 1 one. Put tens with tens and ones with ones: 8 tens and 2 ones, 82. And 61 − 21 the same way: 4 tens and 0 ones, 40.

  1. Show each number as tens and ones: 61 is 6 tens and 1 one.
  2. Add the ones: 1 and 1 make 2.
  3. Add the tens: 6 tens and 2 tens make 8 tens. 8 tens and 2 ones is 82.

A ten and a one are not the same size, so tens go with tens and ones with ones.

The ones make 2, fewer than 10, so nothing trades.

Taking away works the same way: ones from ones, tens from tens.

Ones with ones, tens with tens, adding or taking away.

Adding the 6 tens to the 1 one, as if they were the same size.

Line them up by place: tens with tens, ones with ones. 61 + 21 = 82.

41 + 11 = ___ — 52. Ones with ones: 1 + 1 = 2, fewer than 10, so nothing trades. Then the tens.

42 + 35

Today we'll add two numbers without regrouping. Let's try forty-two plus thirty-five.

First, stack the numbers so the ones line up under the ones, and the tens line up under the tens.

Draw a line under the bottom number. We'll write our answer below it.

Always start with the ones column. Two plus five — what does that make?

Seven! Write seven in the ones place.

Seven is less than ten, so we don't need to regroup. Easy!

42 + 35 = ?Add the ones, then add the tens.tensones42+3577 < 10 ✓7ANSWER7742 + 35
Grade 2 · Stack, add ones, then add tens

Now the tens column. Four tens plus three tens — how many tens is that?

Seven tens! Write seven in the tens place.

Forty-two plus thirty-five is seventy-seven. Great job adding without 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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