Multiplication Whole Numbers I Teacher’s Quality Grant

Multiplication Basic Problem Joe has 4 friends, he receives 3 marbles from each of his friends. How many marbles does Joe receive in total.

What is Multiplication? 3 x 4?

What is Multiplication? Multiplication of 2 numbers a and b, written as a × b, is actually a repeated addition of the number a over b times. Example : 3 × 4 = 4 times of 3 = = 12

What is Multiplication? When you multiply, you join equal-sized groups

Example Each car (#2) holds 4 people. How many people can go on the train ride? 3 X4

Multiplication by Array How can one represent 4 x 5 using a grid?

Multiplication by Array (cont.) 20 shaded squares in the grid represent 4 x 5 =

Multiplication Table How can one calculate 4 x 5 using a the multiplication table?

Multiplication Table (cont.) How can one calculate 4 x 5 using a the multiplication table? 4 5

Multiplication Facts Doubles 2 * 7 = 7 * 2 = = 14 Fives 5, 10, 15, 20, 25, 30, 35, … Nines 09, 18, 27, 36, … (add one to tens and subtract one to ones) Zeros and Ones Any number multiplied by one stays the same Any number multiplied by zero is always zero

Terminology 15X 2 The first number in the multiplication is called the multiplicand, The second number is called the multiplier, and the answer is called the product.

Multiplication Properties There are four properties involving multiplication that will help make problems easier to solve. They are the commutative, associative, multiplicative identity and distributive properties. Commutative property: When two numbers are multiplied together, the product is the same regardless of the order of the multiplicands. For example 4 * 2 = 2 * 4 Associative Property: When three or more numbers are multiplied, the product is the same regardless of the grouping of the factors. For example (2 * 3) * 4 = 2 * (3 * 4)

Multiplication Properties (cont.) Multiplicative Identity Property: The product of any number and one is that number. For example 5 * 1 = 5. Distributive property: The sum of two numbers times a third number is equal to the sum of each addend times the third number. For example 4 * (6 + 3) = 4*6 + 4*3

Final Multiplication Problem Pablo wants to replace the floor tiles in his bathroom. His bathroom measures 6 feet by 7 feet. If he uses square tiles that measure 1 foot by 1 foot, how many tiles will Pablo need to complete this job?