Video: Reading and Writing 18, 19, and 20

In this video, we will learn how to read, write, and model the numbers 18, 19, and 20.

06:53

Video Transcript

Reading and Writing 18, 19, and 20

In this video, we will learn how to read, write, and model the numbers 18, 19, and 20. When we’re counting more than 10 objects, it can be really tricky. It’s easy to lose your place and forget which objects you’ve counted and which ones you haven’t. Can you count the number of gel pens? A good way to count large groups of objects accurately is to place them in groups. When we’re counting more than 10 objects, we could put them in a group of 10 and some more. Let’s try that.

They look much easier to count now. We’ve made a group of 10 and some more. Let’s count the pens which are not in the group of 10, one, two, three, four, five six, seven, eight. What number does 10 and eight make? 10 and eight more is 18. If we add one more pen, we’ll have a group of 10 pens and nine more. What number does 10 and nine make? 10 and nine is 19. If we add one more pen, we’ll have two groups of 10. 10 and 10 makes 20.

Another way to model numbers greater than 10 is to use ten frames. When a ten frame is full, we know it contains 10 objects. This ten frame contains 10 counters, and the other frame has eight counters. 10 and eight is 18, 10 and nine is 19, and two ten frames or two 10s make 20. Let’s practice counting groups of 18, 19, or 20 objects with some questions.

Write the number of apples.

In this question, we need to count the number of apples and then write the number. We know this is a group of 10 apples. It looks just like a ten frame. Now we need to count how many more apples there are, one, two, three, four, five, six, seven, eight. 10 and eight make the number 18. 10, 11, 12, 13, 14, 15, 16, 17, 18. The number of apples is 18.

Which of the following models represents 19?

We’re shown four different models, and each model represents a number. We’re looking for the model which shows the number 19. Let’s look at the first model. There are two ten frames, and each ten frame is full of counters. Which number does 10 and 10 make? 10 and 10 is 20. This model represents the number 20. This is not the one we’re looking for. We’re looking for the model that represents the number 19. Let’s look at our second model. The first ten frame is full; it has 10 counters. And the second ten frame has eight. 10 and eight makes the number 18. This is not the model we’re looking for either.

Let’s try the third model. This model has a 10 and nine more. What number does 10 and nine make? 10 and nine is 19. So this is the model which represents the number 19. 10 and nine more is 19. The final model represents the number 17 because 10 and seven more is 17. We found the model which represents the number 19. 10 and nine more is 19.

How many wooden sticks are there?

We’re shown two bundles of wooden sticks. Before we can tell how many sticks there are altogether, we need to work out how many sticks there are in each bundle. Let’s count them, one, two, three, four, five, six, seven, eight, nine, 10. Both bundles contain the same amount of wooden sticks. There are 10 sticks in each group. What is 10 and 10? 10 and 10 makes 20. 10 and 10 makes 20. There are 20 wooden sticks.

What have we learned in this video? We have learned how to read, write, and model the numbers 18, 19, and 20.

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