Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Multiplication as Repeated Addition: Multiplication is a shortcut for adding the same number multiple times. Imagine a picture of 3 baskets, each containing 4 apples; this can be seen as , which is written as .
Understanding Arrays: An array is a visual arrangement of objects in equal rows and columns. For example, a grid of dots with 2 horizontal rows and 5 vertical columns represents . This helps us see that the total count is the product of the rows and columns.
Division as Equal Sharing: Division is the process of splitting a large group into smaller, equal parts. If you have 15 stickers and share them equally among 3 friends, you can visualize 3 circles with 5 stickers inside each circle, representing .
Division as Equal Grouping: This involves finding how many groups of a certain size can be made from a total. If you have 20 cookies and put 4 on each plate, you are finding how many plates (groups) are needed: .
Commutative Property of Multiplication: The order of the numbers does not change the product. Visually, turning a array (3 rows, 4 columns) on its side makes it a array (4 rows, 3 columns), but both still contain 12 items. So, .
The Relationship Between Multiplication and Division (Fact Families): These operations are opposites (inverses). If you know , you also know and . They form a 'Fact Family' triangle with 20 at the top and 4 and 5 at the bottom corners.
Multiplying by 0 and 1: Any number multiplied by 1 stays the same (), like 1 group of 5 items. Any number multiplied by 0 equals 0 (), like having 5 empty bags with nothing inside.
Skip Counting and Multiples: Multiples are the products of a number and any whole number. On a number line, skip counting by 3s () shows the multiples of 3, which are the answers to the 3 times table.
📐Formulae
💡Examples
Problem 1:
Sarah has 4 boxes. Each box has 6 toy cars. How many toy cars does she have in total? Write a multiplication sentence and use repeated addition to solve.
Solution:
Step 1: Identify the groups and the size. Groups = 4 boxes, Size = 6 cars. Step 2: Write as repeated addition: . Step 3: Write as a multiplication sentence: .
Explanation:
We use multiplication to find the total when we have multiple groups of the same size. Adding 6 four times is the same as multiplying 4 by 6.
Problem 2:
There are 18 cupcakes to be shared equally among 3 children. How many cupcakes does each child get? Show the related multiplication fact.
Solution:
Step 1: Identify the total (18) and the number of groups (3). Step 2: Set up the division: . Step 3: Find the related multiplication fact: .
Explanation:
To solve a division problem, we can ask ourselves '3 times what number equals 18?'. Since , then .