Hi there! My name is Caroline, and I have a confession: I have a huge sweet tooth!
As soon as I finish eating dinner, I'm always ready for dessert. My favorite
treat to have for dessert is cookies. Doesn't matter if they're chocolate chip cookies,
sugar cookies, oatmeal raisin cookies - I love them all!
The thing is, I try not to eat too many, but I always feel like I could eat just one more
cookie. Last night, I ate two cookies, but I felt like I could eat - well,
one more than two. But what does that really mean, "one more"? How many is that? Let's find out!
Let's talk about our goals for today. By the end of this lesson,
you should be able to find one more or one less than any number between 0 and 10. We'll start
by learning how counting can help us find one more or one less than a number. Then,
we'll practice some examples together. Let's get started!
This is a math tool called a number line. It helps to see numbers in the order we
count them in. Let's use this number line to count from 0 all the way up to 10. Ready?
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. We can also use a number line to help us count backward!
This time, let's count from 10 all the way down to 0. Ready? 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.
We can even start somewhere in the middle of a number line like at 5. Then, we can count
forwards from 5, like 5, 6, 7, or backward from 5, like 5, 4, 3, by using the numbers around it.
When we count forwards and backward, there is a pattern in how the numbers
change. Can you tell what it is? Let's take a closer look.
We're going to focus on this part of the number line that shows the numbers 3, 4, and 5.
When we count, we say these numbers right after each other. Each number we say when counting up
is one more than the number before it. That means 4 is one more than 3, and 5 is one more than 4.
We can double-check this on a math tool we always have with us - our fingers! Hold
up 3 fingers with me. Now, put up one more finger. How many fingers do you have up now?
Four! That's because 4 is one more than 3.
So, when we count up, each number is one more than the number before it. But, what about when
we count down, or backward? Each number we say when counting down is one less than the number
before it. That means 4 is one less than 5. So, what's one less than 4? Practice using
your fingers or this number line to find out. You can pause the video here and try it for yourself.
If we hold up 4 fingers, then put one down, we have 3 fingers left up. We can also see
that 3 comes right before 4 on our number line. That means 3 is one less than 4.
So, let's think about what this all means. When we count forward, each number is one
more than the number before it. That's why numbers get bigger as we keep counting up.
When we count backward, each number is one less than the number before it. That's why numbers get
smaller as we keep counting down. This pattern is why counting is one of our best tools for finding
one more or one less. Let's try counting to solve a few practice problems together.
Here's our first problem. What number is one more than 8? Pause and try to find the answer.
We are trying to find one more than 8. Should we count up or down? We know that when we count up,
each number is one more than the number before. So, let's count up from 8. What number comes
right after 8 when we count? 9! You can see in our number line that 9 is one more than 8.
Now, what if we wanted to find one less than 8? What should we do? If you're able,
point up if you think we should count up, and point down if you think we should count down.
We're going to count down to solve this because each number we say when we count down is one
less than the number before it. So, if we start counting down from 8, what number should we say?
7! 7 is right before 8 on the number line, so 7 is one less than 8.
Phew - all this math is making me hungry and I could really go for some cookies right now...
Hey, that reminds me! Now, we can figure out how many cookies I'd have if I ate one more than 2!
What do you think? If I usually eat 2 cookies for dessert, but I decide to eat one more than 2,
how many would I eat? You can pause the video here and use any of the strategies we've learned about
to find your answer. If you said 3, you're right! To find one more, we count up. That
takes us from 2 to 3. It sounds like I'm going to be eating 3 cookies for dessert from now on!
I hope that doesn't give me a stomachache...
Thanks for helping me figure that out! Now, you know how to find one more or
one less than any number within 10. Be sure to complete the extra practice activities
in your PDF. These will help you become an expert at finding out one more and one less.
We do this kind of math all the time in the real world, so it's an important skill to practice.
And if you happen to have any cookies around while you're practicing, think about how many
you'd have if you had one less. Then, maybe you can save that extra one for me! See you soon!