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Subtract within 20 without Regrouping

Students subtract within 20 when no regrouping is required (e.g., 18 − 5 = 13). They subtract ones from ones.

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Subtract within 20 without Regrouping

Grade 1 · Counting, Fluency, and Fact Strategies · question 1 of 3

0 of 12

12 rungs. A star at the top.

− 3 = 11

How it is taught

0:00 of 2:45

No regrouping means the ones are big enough.

You subtract ones from ones.

Read it: Take from the ones: the 10 stays

17 − 4. 17 is 10 and 7. The 10 stays; take 4 from the 7: 3 are left. So 17 − 4 = 13.

  1. Split the teen: 17 is 10 and 7.
  2. Take 4 from the 7 ones: 3.
  3. Put the 10 back with them: 13.

The ones have enough to take 4, so the 10 does not change.

7 − 4 = 3, and 10 and 3 is 13.

Only the ones digit goes down: 17, then 13.

When the ones have enough, take from the ones. The 10 stays.

Taking the 4 from the 10 and getting 7.

The 10 stays. Take from the 7 ones: 13.

19 − 4 = ___ — 15. The 10 stays: 9 − 4 = 5, so 15.

18 − 5

Imagine you have eighteen grapes. You eat five of them. How many grapes are left?

Let's use a number line. Here's eighteen, where we start.

Now we hop back five times: seventeen, sixteen, fifteen, fourteen, thirteen.

We land on thirteen! That's our answer on the number line.

Now let's write it as a subtraction: eighteen take away five.

Start with the ones column. Eight is on top, five is on the bottom.

What is eight minus five?

18 grapes. Eat 5. How many left?0201318start− 51318−58 − 5 = ?31ANSWER13grapes left
Grade 1 · Take ones from ones — no regrouping needed

Three! Write three in the ones place.

There's nothing to subtract from the tens, so the one just comes straight down.

Eighteen minus five is thirteen. We took five ones away from eight ones — no regrouping needed!

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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