Multiplication (Number Sense)

Multiplication is a simpler way to do repeated addition. For example: 4 x 6 is easier than 4 + 4 + 4 + 4 + 4 + 4. You are also less likely to make a careless error using multiplication than if you use repeated addition.

An array is a way of ordering objects in rows and columns to make a rectangular shape. In an array, all the rows are equal to each other and all the columns are equal to each other and that makes a rectangular shape. For example:

The zero property of multiplication is that any factor multiplied by 0 equals 0. For example: 5 x 0 = 0

The identity property of multiplication is that any factor multiplied by 1 equals the original factor. For example: 3 x 1 = 3

The commutative property of multiplication is that two factors can be multiplied in either order and give the same answer. For example: 7 x 2 = 2 x 7

The associative property of multiplication is that three or more factors can be multiplied in different groups and still give the same answer. For example: (4 x 5) x 6 = 4 x (5 x 6)

A number is a factor of another number if it divides into it evenly without a remainder. To find factors of a number you can make a factor rainbow. See the example below: The factors of 24 are 1, 2, 3, 4, 6, 8, 12, and 24.

1 2 3 4 6 8 12 24

Prime numbers are numbers that can only be divided evenly by 1 and themselves. For example: 7 is a prime number because it only has 2 factors. These factors and 1 and 7.

Composite numbers are numbers that have more than 2 factors. For example: 4 is a composite number because its factors are 1, 2, and 4.

Since 0 has no factors it is not prime or composite.

Since 1 has only 1 factor it is not prime or composite.

A multiple can be made by multiplying a number. For examples: some multiples of 6 are 6, 12, 18, 24, 30, 36 etc because 1 x 6 = 6, 2 x 6 = 12, 3 x 6 = 18, 4 x 6 = 24, 5 x 6 = 30, 6 x 6 = 36, etc.