Subtraction Number Sentences Video

When you watch the red ball bounce up and down the number line, you can write a number sentence that shows where the ball goes. It’s easy! Let’s learn how.
Let’s start the ball on number 3, and begin our number sentence with 3. Whenever the ball bounces backward, we add a minus sign to our number sentence.
The ball bounced backward two spaces, so let’s put a two in our number sentence. Looks like the ball is done bouncing, so we can put an equal sign in our number sentence.
Now our number sentence reads: “Three minus two equals.” What’s the answer? One! And look where the ball landed. On number one!
This time, let’s start the ball on number eight. Which number goes first in our number sentence? That’s right, number eight. The ball bounces backwards four spaces. Do we put a plus or a minus sign when the ball bounces backwards?
You got it, a minus sign! And since the ball bounced four spaces, we’ll put number four in our number sentence.
And now that the ball is done bouncing, we can put down an equals sign.
So our number sentence is: “Eight minus four equals…” And what does it equal? Four, right where the ball landed!
This time, watch the ball carefully, and see if you can write the number sentence that tells the story of his bounces.
Great, the ball started on number ten, bounced backward seven times, and landed on number three. So our number sentence is “Ten minus seven equals three.”
Let’s try a word problem using the number line. “There are six slices of pizza. The kids at the party ate five. How many slices of pizza are left?”
Here’s the pizza, fresh from the oven! Where should the ball start on the number line?
That’s right, on number six, because there are six slices. Let’s put a six in our number sentence. The kids at the party eat five slices. Which direction will the ball bounce?
Yes, the ball will bounce backwards. So that means we put a minus sign in the number sentence. How many spaces will the ball bounce?
Right again, he will bounce back five spaces, because the kids ate five slices. Let’s put that five in our number sentence. And six minus five equals…?
Look where the ball landed. He’s on number one! Six minus five equals one, and there is one slice of pizza left.
Awesome work writing number sentences today!