Skip Counting with Arrays
In this video, we will learn how to make arrays with up to five rows or columns and use skip counting and addition to find the total number of objects in an array.
An arrangement of objects or pictures in rows or columns is called an array. We could group these soldiers into two rows. Each of these rows contains five soldiers. To find the total number of soldiers in this array, we could add together the two rows of five. We know that five plus five equals 10. So, we could say two rows of five is 10.
An array is a group of objects grouped together in either rows or columns. This array has five columns, and each column contains two soldiers. We could find the total number of soldiers by adding together our five groups or five columns of two. In other words, we would need to add two plus two plus two plus two plus two. Two plus two is four. Four plus two is six. Six plus two is eight. And eight plus two is 10.
Another way we can find the total number of soldiers in this array is to skip count by two. Two, four, six, eight, 10. Let’s try some example questions to help us practice skip counting and adding to find the total number of objects in an array.
An array can be used to model equal groups of objects. Which of the following is not an array?
We’re shown five different groups of objects. One of these groups is not an array, which means all the other groups are arrays. Which of these groups is not an array? An array is when objects are grouped together in equal rows, or columns. This is an array. This array shows three columns, and each column contains three dots. This is an array. We can group the dots in the second picture into three rows of two, so we know this picture is also an array.
This picture shows one row of four dots. It’s an array. This picture shows three rows, but the rows are not equal. The first row contains four dots, but the second row only contains three, and the third row contains four dots. If the rows are not equal, this is not an array. So, this is the model which is not an array.
The cupcakes are in an array. How many rows are there? How many cupcakes are in each row? How many cupcakes are in the array?
We’re shown an array of cupcakes. How many rows are there in the array? There’s one row, two rows. Now, we need to work out how many cupcakes there are in each row. One, two, three. How many cupcakes are there altogether in the array? To find the total number of cupcakes, we could add together the two rows of three. What is three plus three? The answer is six. Another way we could find the answer is to skip count in threes. One three is three. Two threes make six. Three, six, we skip counted by three. There are six cupcakes in the array.
Madison is using skip counting to count the number of fish. She sees that there are three fish in each row, so she can skip count by threes. She says, three, six, what, what. How many fish are there?
To find out the total number of fish in the array, we need to skip count in threes. Madison started to skip count. Three, six. What comes next? Three, six, nine. Three, six, nine, 12. Four rows of three makes 12. Three, six, nine, 12. Madison found the answer by skip counting.
What have we learned in this video? We’ve learned that an array is a group of objects arranged in rows or columns. And we can find the total number of objects in an array by adding or skip counting.