Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Multiplication is the process of Repeated Addition. For example, means adding three times: . Visually, this can be seen as rows of dots each forming a rectangular grid totaling dots.
Terminology: In a multiplication sentence like , the number being multiplied () is the Multiplicand, the number of times it is multiplied () is the Multiplier, and the result () is the Product.
Order Property (Commutative Property): Changing the order of the numbers does not change the product. For example, and . Visually, a grid of rows and columns is simply a rotated version of a grid with rows and columns.
The Identity Property of One: Any number multiplied by stays the same (). Visually, this is like having one single group containing items.
The Zero Property: Any number multiplied by results in (). Visually, this represents having multiple groups (like boxes) but with nothing inside them, resulting in a total of zero.
Multiplication on a Number Line: Multiplication can be visualized as taking equal-sized jumps. To solve , you start at and take jumps of units each, landing on and finally .
Patterns in Tables: Specific tables have recognizable patterns. For example, the table of always ends in the digits or (), and the table of always ends in ().
Doubling and Halving: Knowing the table of helps with the table of . Since is double of , the results in the table of are double the results in the table of . For example, , so .
📐Formulae
(Commutative Property)
(Identity Property)
(Zero Property)
💡Examples
Problem 1:
Calculate the total number of legs on spiders, if each spider has legs.
Solution:
Step 1: Identify the number of groups. There are spiders. \ Step 2: Identify the number of items per group. Each spider has legs. \ Step 3: Set up the multiplication: . \ Step 4: Use the table of : . \ Step 5: The product is .
Explanation:
Since there are equal groups of legs, we multiply the number of spiders by the number of legs per spider.
Problem 2:
Find the missing number:
Solution:
Step 1: Recall the Commutative Property of multiplication, which states . \ Step 2: In the expression , the factors are and . \ Step 3: To keep the product the same when is written first, the second factor must be . \ Step 4: and . \ The missing number is .
Explanation:
This example demonstrates that the order of numbers in multiplication does not change the final result.