1. UNIT I DECIMAL NUMBERS Content Next

2. OVERVIEW OF THE MODULAR WORKBOOK In this modular workbook, you will understand the concept of the language of decimal numbers. This modular workbook, will help you to read, write, and name decimal numbers for a given models, standard, mixed and technical and science work form. It provides the knowledge about place value, with the aid of a place - value chart. It also provides information on how to compare and order decimal numbers and also how to round off decimal numbers. This module will provide you a more difficult work in mathematics. Exercises will help the learners evaluate themselves to understand decimal numbers. Back Next

3. OBJECTIVES OF THE MODULAR WORKBOOK After completing this modular workbook, you expected to: 1. Know the language of decimal numbers. 2. Read, write, and name decimal numbers in different forms. 3. Read and write decimal numbers with the aids of place - value chart. 4. Compare and order decimal numbers. 5. Rounding off decimal numbers by following its rule. Back Next

5. One important feature of our number system is the decimal. It involved many computational operations. It is very useful in the measurement of very thin sheets and in the computation involving in exact amount. But what is decimal? Look at the following examples: Back Next

7. From the example given above, a “ decimal ” may be defined as a fraction whose denominator is in the power of 10. Back Next

8. Numbers in the power of 10 are 10, 100, 1000, 1000, etc. The dot before a digit in a decimal is called “ decimal point ” which is an indicator that the number is a decimal. The place on the position occupied by a digit at the right of the decimal point is called a “ decimal place ”. Back Exercises

9. I. Give the meaning and explain the use of the following. 1. What are decimals? 2. What is decimal point? 3. What is decimal place? 4. Give some examples of decimal numbers. Back Next 1 Worksheet

11. II. Change the decimal numbers to fractional form. Example: 0.8 = 8 10 1. 0.9 =_______________ 2. 0.1 =_______________ 3. 0.04 =_______________ 4. 0.06 =_______________ 5. 0.09 =_______________ 6. 0.001 =_______________ 7. 0.009 =_______________ 8. 0.0071 =_______________ 9. 0.0009 =_______________ 10. 0.0003 =_______________ Back Next

12. 11. 0.0004 =________________ 12. 0.0005 =________________ 13. 0.00008 =________________ 14. 0.00009 =________________ 15. 0.148 =________________ 16. 0.79 =________________ 17. 0.1459 =________________ 18. 0.6 =________________ 19. 0.01 =________________ 20. 0.051 =________________ Back Home

14. How to read and write decimals or decimal numbers? A decimal is read and write according to the number of decimal place it has. Here are the rules in reading and writing decimal numbers. Back Next

15. RULE I. A decimal of one decimal place is to be read and to be written as tenth. .4 is read as “4 tenths” and is to be written as “four tenths”; 4/10 .2 is read as “2 tenths” and is to be written as “two tenths”. 2/10 Back Next

16. RULE II. A decimal of two decimal places is to be read and to be written as hundredth. .35 is read as “35 hundredths” and is to be written as “thirty – five hundredths”; 35/100 .43 is read as “43 hundredths” and is to be written as “forty – three hundredths”.43/100 Back Next

17. RULE III. A decimal of three decimal places is to be read and written as thousandth. .261 is read as “261 thousandths” and is to be written as “two hundred sixty – one thousandths”; 261/1000 .578 is read as “578 thousandths” and is to be written as “five hundred seventy – eight thousandths”.578/1000 Back Next

18. RULE IV. A decimal of four decimal places is to be read and to be written as ten thousandth. .4917 is read as “4917 ten thousandths” and is to be written as “four thousand, nine hundred seventeen ten thousandths”; 4917/10,000 .5087 is read as “5087 ten thousandths” and is to be written as “five thousand eighty - seven ten thousandths”.5078/10,000 Back Next

19. A decimal is read and written like an integer with the name of the order of the right most digits added. Back Next tenths hundredths thousandths ten thousandths hundred thousandths Millionths ten millionths hundred millionths billionths ten billionths hundred billionths trillionths 0 . 4 3 5 7 8 9 6 1 2 5 3 4

20. Note: the names of the order of the different decimal places. Quadrillionths Pentillionths Hexillionths Heptillionths Octillionths Nonillionths Decillionths Undecillionths Dodecillionths Tridecillionths… SEQUENCES Back Next

22. 0.43578 Read as forty-three thousand, five hundred seventy-eight hundred thousandths. 0.435789 Read as four hundred thirty-five thousand, seven hundred eighty nine millionths. 0.4357896 Read as four million, three hundred fifty-seven thousand, eight hundred ninety-six ten millionths. Back Next

23. 0.43578961 Read as forty three million, five hundred seventy-eight thousand, nine hundred sixty-one hundred millionths. 0.435789612Read as four hundred thirty-five million, seven hundred eighty nine thousand, six hundred twelve billionths. 0.4357896125 Read as four billion, three hundred fifty seven million, eight hundred ninety six thousand, one hundred twenty five ten billionths. Back Next

24. 0.43578961253 Read as forty-three billion, five hundred seventy eight million, nine hundred sixty-one thousand, two hundred fifty three hundred billionths. 0.435789612534 Read as four hundred thirty-five billion, seven hundred eighty-nine million, six hundred twelve thousand, five hundred thirty-four trillionths. Back Exercises

25. I. Write each decimal numbers in words on the space provided. 1. 0.167213143____________________________ ______________________________________ 2. 0.52541876_____________________________ ______________________________________ 3. 0.263411859____________________________ ______________________________________ 4. 0.984562910____________________________ ______________________________________ 5. 0.439621512____________________________ _______________________________________ Back Next 2 Worksheet

26. II. Write the decimal number in standard form. 1. Nine tenths ______________________________________________ 2. Four hundredths ______________________________________________ 3. Two thousand, two hundred and two hundred thousandths ____________________________________________ 4. Four hundred seventy – six millionths ________________________________________________ 5. Forty thousand, one hundred forty – one millionths ________________________________________________ Back Home