Lesson

Subtraction as Taking Away

Students learn that subtraction means starting with a whole set and taking some away within 20.

Subtraction as Taking Away

What students learn

Students learn that subtraction means starting with a whole set and taking some away within 20. Begin with to see the set before anything is removed.

Why it matters

Taking away is one of the most familiar ways to solve subtraction problems. Students use it when they share snacks, give away objects, or count what is left. shows the step where the change happens.

Learn the idea

In subtraction, the starting number is the whole set and the answer tells what remains. Use to help the student notice that the difference is the part left over.

Try it

Put 12 counters in a row, take away 4, and ask the student to say how many are left. Then repeat with 18 take away 7 and have them explain how they found the answer.

Parent guide

Use take-away language first, then connect it to the minus sign. If the student loses track while counting, have them move objects one by one instead of counting in the air. Praise careful matching of the removed group to the remaining set.