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Subtracting Means Taking Some Away · Early Operations · CCSS.MATH.CONTENT.K.OA.A.1 · subtraction

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Subtracting Means Taking Some Away

with Lumi

Lumi sits at a sunny picnic table with five shiny red apples in a bowl, grinning as she picks up two apples and places them into a basket beside her, showing the now-smaller group left in the bowl.

Identify subtraction as the action of taking items away from a group.
Count how many items remain after some are removed.
Show that the group gets smaller after items are taken away.
Count how many objects remain when items are taken away from a small group.

Key terms

subtraction: Taking some items away from a group of items.
difference: The number of items that are left after taking some away.
minus sign: The little − symbol that tells you to take away.
take away: To remove items so the group becomes smaller.

Taking Items Away

Subtraction is the action of removing some items from a group. You begin with a starting number of objects, then you take a certain number out and set them aside. Because you removed objects, the group that is left is smaller than it was at the start. This is why subtracting always gives an answer that is the same or smaller, never bigger.

Counting What Is Left

To find a subtraction answer, count what stays behind after you take items away. First count the starting group, then take away the right number of objects, and finally count only the objects that remain. The number left over is called the difference. Saying it as a sentence helps: five take away two equals three, written 5 − 2 = 3.

Worked examples

Find 5 apples take away 2 apples.

Start with 5 apples in the bowl.
Take 2 apples out and set them aside.
Count what is left: 1, 2, 3.

Answer: 3 apples

There are 4 frogs on a log and 1 hops off.

Start with 4 frogs on the log.
Take 1 frog away.
Count the frogs left: 1, 2, 3.

Answer: 3 frogs

Hi! I am Lumi, and I love apples. Look at my bowl. I have 5 apples. That is my starting number. Now I take 2 apples out of the bowl. I put them in the basket. Taking apples away is called subtracting. Let us count what is left in the bowl: 1, 2, 3. Only 3 apples are left! 5 take away 2 equals 3. We write it like this: 5 - 2 = 3. When we take some apples away, the group gets smaller. We end up with fewer apples than we started with! Here is a hint: count everything first, then count how many you are taking away, and count what stays behind. That is your answer!

Activity

Now let us practice with stars the same way Lumi did with apples. Drag the stars into the take-away box to remove them and see what is left.

Practice

Nora has 6 stickers and gives 2 away; how many are left?

Start with 7 blocks, take away 3, and count what remains.

Common mistakes to avoid

Subtraction makes the number biggerTaking items away makes a group smaller, so the answer is fewer than the starting number, not more.
The answer is the amount removedThe answer is how many items stay behind, not how many you took away from the group.

Check your understanding

There are 4 frogs on a log. 1 frog jumps into the pond. How many frogs are still on the log?

Sam has 6 grapes. He eats 3 of them. Does Sam have MORE grapes or FEWER grapes now?

There are 5 birds on a fence. 2 birds fly away. How many birds are left on the fence?

Recap

Subtraction means taking some items away from a group, which makes the group smaller. To find the answer, called the difference, count the starting group, take away the right number, and count only the items that remain.

Reflect

When have you taken something away and ended up with fewer than you started with?