Unit 3 Multiplication of Whole Numbers Basic Principles

Unit 3 Multiplication of Whole Numbers

Basic Principles of Multiplication of Whole Numbers • Multiplication is actually a simple method of addition. – For example, if three 7 s are added, the answer is 21. – If the number 7 is multiplied by 3, the answer or product is equal to 21. – Therefore, 7 + 7 is the same as 3 x 7.

Basic Principles of Multiplication of Whole Numbers • To multiply numbers, write the number to be multiplied, or the multiplicand, first. – If possible, it is best to use the larger of the two numbers as the multiplicand. – The product of 645 x 25 is the same as the product of 25 x 645, but it is easier to use 645 as the multiplicand.

Basic Principles of Multiplication of Whole Numbers • Under the multiplicand, write the number of times it is to be multiplied, or the multiplier, aligning the two numbers on the right side. – Every number in the multiplicand is then multiplied by every number in the multiplier. – After all of the multipliers are used, the products obtained are added together to get the final product.

Multiplication of Whole Numbers • Example: Multiply 645 by 25 – Use the larger number as the multiplicand:

Multiplication of Whole Numbers • Multiply: • Add the products obtained to get the final product:

Practical Problem • A registered nurse (RN) is giving a patient 250 milligrams (mg) of tetracycline 6 times a day. • How many mg of tetracycline is he giving the patient per day?

Practical Problem • Multiply 250 x 6: • The RN gives the patient 1, 500 mg of tetracycline each day.