Place Value A digit is a number 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 that names a place-value location. For large numbers, digits are separated by commas into groups of three, called periods. Each period has a name: ones, thousands, millions, billions, trillions, and so on. Ones Thousands Millions Billions Trillions PLACE-VALUE CHART Hundreds Tens Ones Thousands Millions Billions Trillions PLACE-VALUE CHART Hundreds Tens 6 3 7 4 8 0 2 8 9 5 2 63 billions, 748 millions, 28 thousands, 952 ones Next Slide

When a whole number is written using the digits 0  9 it is said to be in the standard form. The position that each digit occupies determines its place value. Example 1. What does the digit 4 mean in each number? a. 4 thousands b. 4 hundred thousands c. 4 billions Solution a. 234,598 b. 456,901 c. 24,355,567,222 Your Turn Problem #1 1. 573,289 2. 213,570 3. 37,218,021,593 Solution What does the digit 7 mean in each number? 1. 7 ten thousands 2. 7 tens 3. 7 billions Next Slide

Writing numbers in expanded notation. 34,123 = 3 ten thousands + 4 thousands + 1 hundred + 2 tens + 3 ones = 30,000 +4,000 + 100 + 20 + 3 This number can be written in what is called expanded form, shown below: Standard Notation: 34,123 Example 2. Write 74,289,416 in expanded notation. Answer: 70,000,000 + 4,000,000 +200,000 + 80,000 + 9,000 + 400 + 10 + 6 Your Turn Problem #2 Write 5,034,319 in expanded notation. Answer: 5,000,000 + 30,000 + 4,000 + 300 + 10 + 9

seven hundred eighty-nine Writing numbers in words. Procedure: When asked to rewrite a number using words: Proceeding left to right, write in words the number in each period, then write its period name (example: trillion, million, etc...), then write a comma, then proceed to the next period, etc... Note: The period on the right (the last period) has no period name. Notes: 1. Commas are used after each period. 2. The word “and ” is only used for numbers which have decimals. 3. Hyphens are used for the numbers 21-99 except for the multiples of 10. Examples: 23: twenty-three 57: fifty-seven 40: forty (no hyphen is necessary) Example 3. Write a word name for the following. a) 123 = one hundred twenty-three = fifty-six thousand, seven hundred eighty-nine b) 56, 789 Answers a) 123. b) 56,789. Your Turn Problem #3 b) 3,429,718. a) 9,207 a) Nine thousand, two hundred seven Three million, four hundred twenty-nine thousand, seven hundred eighteen Answers

Example 4a. Three million, two hundred thirty-five thousand, eight hundred eleven Writing numbers with digits instead of words Procedure: When asked to rewrite a written number in words into numbers using digits: Proceeding left to right, for each period (separated by commas) write the number using digits and place commas where they are placed in the written form using word. If a period is not written, write “000”, and continue to the next period. Example 4b. Four billion, twenty million, three hundred forty-eight 3, 235, 811 Solution: 3,235,811 4, 20, 000, 348 Solution: 4,020,000,348 Note: 000 is for the thousands period. Your Turn Problem #4 a) One hundred thirty-five thousand, four hundred two b) Four billion, four hundred eight thousand, forty-six b) 4,000,408,046 a) 135,402 Answers The End B.R. 6-1-08