MATH01L17: Multiplication as Repeated Addition
OBJECTIVES
Show the relationship between multiplication and addition.
LESSON PREREQUISITE
Addition and Subtraction Concept
LESSON PROPER
What is a Fact Family?
Multiplication is repeated addition.
Addition sentence: 3 + 3 + 3 + 3 = 12
Multiplication sentence: 4 x 3 = 12
Multiplication means putting things together in an equal number of groups.
The numbers to be multiplied are called factors.
4 x 3 = 12
4 and 3 are called FACTORS.
Product is the answer in the multiplication. 12 is called the PRODUCT. “x“ is the symbol for multiplication.
EXAMPLE 1:
Mary prepared 5 plates of cupcakes. Each plate has 3 cupcakes. How many cupcakes are there in all?
How many groups were there? 5 groups.
How many cupcakes were there in each plate? 3 cupcakes.
How many cupcakes were there in all? 15 cupcakes.
Addition sentence 3 + 3 + 3 + 3 + 3= 15.
5 groups of 3 is 15. 5 times 3 is 15.
Multiplication sentence: 5 x 3 = 15.
EXAMPLE 2:
There are 4 trays of eggs. Each tray has 6 eggs. How many eggs are there in all?
How many groups are there? 4 groups.
How many eggs are there in each tray? 6 eggs.
How many eggs are there in all? 24 eggs.
Addition sentence: 6 + 6 + 6 + 6 = 24.
Multiplication sentence: 4 x 6 = 24
EXAMPLE 3:
There are 3 baskets of apple. Each basket has 7 apples. How many apples are there in all?
How many groups are there? 3 groups.
How many apples are there in each basket? 7 apples.
How many apples are there in all? 21 apples.
Addition sentence: 7 + 7 + 7 = 21
Multiplication sentence: 3 x 7 = 21
Multiplication Sentence to Addition Sentence
3 x 4 = 4 + 4 + 4 4 x 3 = 3 + 3 + 3 + 3
Addition Sentence to Multiplication Sentence
2 + 2 + 2 = 6
3 x 2 = 6
5 + 5 = 10
2 x 5 = 10
4 + 4 + 4 + 4 + 4 = 20
5 x 4 = 20