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# 1: Whole Numbers

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Even though counting is first taught at a young age, mastering mathematics, which is the study of numbers, requires constant attention. If it has been a while since you have studied math, it can be helpful to review basic topics. In this chapter, we will focus on numbers used for counting as well as four arithmetic operations—addition, subtraction, multiplication, and division. We will also discuss some vocabulary that we will use throughout this book.

• 1.1: Introduction to Whole Numbers (Part 1)
Much like learning a language, learning algebra begins with getting to know the basic vocabulary. As you continue to learn, you add to your vocabulary and practice it often so that it because easy. In algebra, numbers and symbols are used like words and ideas in a language. The most basic numbers used in algebra are those we use to count objects.
• 1.1: Introduction to Whole Numbers (Part 2)
The process of approximating a number is called rounding. Numbers are rounded to a specific place value depending on how much accuracy is needed. The place value to which we round to depends on how we need to use the number.
• 1.2: Add Whole Numbers (Part 1)
The identity property of addition describes how the sum of any number a and 0 is the number a. The commutative property says that changing the order of the addends a and b does not change their sum. To add whole numbers, we first write the numbers so each place value lines up vertically. Then, we add the digits in each place value, working from left to right starting with the ones place. If a sum in a place value is more than 9, carry to the next place value.
• 1.2: Add Whole Numbers (Part 2)
To solve real-world problems, we first need to read the problem to determine what we are looking for. Then we write a word phrase that gives the information to find it. Next we translate the word phrase into math notation and then simplify. Finally, we translate math notation into a sentence to answer the question.
• 1.3: Subtract Whole Numbers (Part 1)
To subtract whole numbers, we first write the numbers so each place value lines up vertically. Then, we subtract the digits in each place value, working from left to right starting with the ones place. If the digit on top is less than the digit below, borrow as needed. In the end, we check our answer by adding the difference of the two numbers to one of the two numbers to see if we get the other number.
• 1.3: Subtract Whole Numbers (Part 2)
To solve real-world problems, we first need to read the problem to determine what we are looking for. Then we write a word phrase that gives the information to find it. Next we translate the word phrase into math notation and then simplify. Finally, we translate math notation into a sentence to answer the question.
• 1.4: Multiply Whole Numbers (Part 1)
To multiply two whole numbers, first write the numbers so each place value lines up vertically. Then, start with the ones place in the bottom number and multiply the bottom number by the ones digit in the top number, then by the tens digit, and so on. Next, write the partial products, lining up the digits in the place values with the numbers above. Insert a zero as a placeholder with each additional partial product. Finally, add the partial products.
• 1.4: Multiply Whole Numbers (Part 2)
To solve real-world problems, we first need to read the problem to determine what we are looking for. Then we write a word phrase that gives the information to find it. Next we translate the word phrase into math notation and then simplify. Finally, we translate math notation into a sentence to answer the question.
• 1.5: Divide Whole Numbers (Part 1)
To divide whole numbers, divide the first digit of the dividend by the divisor. If the divisor is larger than the first digit of the dividend, divide the first two digits of the dividend by the divisor, and so on. Write the quotient above the dividend. Multiply the quotient by the divisor and write the product under the dividend. Subtract that product from the dividend. Bring down the next digit of the dividend. Repeat the process until there are no more digits in the dividend to bring down.
• 1.5: Divide Whole Numbers (Part 2)
To solve real-world problems, we first need to read the problem to determine what we are looking for. Then we write a word phrase that gives the information to find it. Next we translate the word phrase into math notation and then simplify. Finally, we translate math notation into a sentence to answer the question.
• 1.E: Whole Numbers (Exercises)
• 1.S: Whole Numbers (Summary)

Figure 1.1 - Purchasing pounds of fruit at a fruit market requires a basic understanding of numbers. (credit: Dr. Karl-Heinz Hochhaus, Wikimedia Commons)