UNIT 5. DECIMAL NUMBERS
1. DECIMAL NUMERAL SYSTEM
1. Read the following paragraph
When you divide the unit relating to the base of ten, you can use the decimal notation to represent these quantities. Thus,
 A tenth is each of the parts obtained by dividing the unit into ten equal parts. It is 1:10 = 0.1
 A hundredth is each of the parts obtained by dividing the unit into a hundred equal parts, that is, a tenth into ten parts. It is 1:100 = 0.01
 A thousandth is each of the parts obtained by dividing the unit into a thousand equal parts, that is, a tenth into a hundred parts or a hundredth into ten parts. It is 1:1000 = 0.001
2. In your notebook, write down the meaning of the words: Tenth, hundredth and thousandth and the Spanish definition.
3. Do the following interactive exercises relating to decimal numbers
2. REPRESENTATION OF DECIMAL NUMBERS ON A LINE
1. Try the following interactive exercise. Just do “La recta real”
2.Do this exercise
3. Now draw a line in your notebook and represent the numbers 2.34, 4.51 and 0.56. Use a different line for each number
3. ORDERING DECIMAL NUMBERS
1. Read the following paragraph
 Ordering decimals means putting them in order from smallest to largest or from largest to smallest.
 Line up the decimal points.
 Compare the digits in each column, starting on the left.Write down place value headings if it helps you.
 Below we are comparing 0.459 and 0.495 to see which is bigger.
Both numbers have 0 units. So look in the tenths column.
Both numbers have 4 tenths. So look in the hundredths column.
0.495 has 9 in the hundredths column whereas 0.459 only has 5 in the hundredths column. (There is no need in this example to compare the thousandths column.) So 0.495 is bigger than 0.459.
2. In your notebook compare the numbers 2.203 and 2.23 using the same procedure but explain it in Spanish
3. Do the interactive exercise below
Do exercise 1, exercise 2 and exercise 3
4. CONVERTING DECIMALS TO FRACTIONS
1. Read the following paragraph
 To change a fraction to a decimal, divide the top number (the numerator) by the bottom number (denominator).
 A decimal fraction with one decimal place is written as tenths.
 A decimal fraction with two decimal places is written as hundredths.

A decimal fraction with three decimal places is written as thousandths
2. Now, practice with the following exercise but only pages 12 and 13
3. Write down the numbers 2.34, 15.209 and 0.87 as fractions in your notebook
5. OPERATIONS WITH DECIMALS
1. Do all the exercises below to practice additions, subtractions, multiplications and divisions
6. MULTIPLICATION AND DIVISION OF UNITS WITH ZEROS
1. Read the following websites to find out how to do these multiplications and divisions. Do 15 exercises of multiplications and 15 of divisions. You also can see the following video
http://www.gobiernodecanarias.org/educacion/usr/eltanque/todo_mate/mult_deci/mult_deci_p.html
http://www.gobiernodecanarias.org/educacion/usr/eltanque/todo_mate/divi_deci/divi_deci_p.html
2. Write down how to do this kind of multiplications and divisions in your notebook and copy some examples.
7. ROUNDING DECIMALS
1. Do the exercise REDONDEO in the following website. First write down how to round decimals in your notebook.
http://w3.cnice.mec.es/recursos/primaria/matematicas/decimales/menuu4.html
2. Now do the following test but rounding to the next whole number.
http://teachingtreasures.com.au/maths/decimalsk3/roundingdecimals23.htm
8. COMPARING DECIMALS, FRACTIONS AND PERCENTAGES
1.Watch this video and you will learn how to change fraction and decimals into percentages
http://www.mathplayground.com/howto_perfracdec.html
2.Now do the following interactive activities to check what you know about this
http://www.quia.com/cb/34887.html
3.Do the following exercises in your notebook
4. Now check the answers
9.SOME TEST TO REVIEW
http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/decimals/usingdecimals/quiz.shtml
http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/comparing/comparingall3/quiz.shtml
http://www.bbc.co.uk/schools/ks2bitesize/maths/tests/decimals.shtml
Book exercises results. Press here to check
¡¡una calculadora muy completa y muy chula!!
by Curiosidades matemáticas February 11, 2009 at 4:31 pmGreat site, how do I subscribe?
by Kelli Garner October 3, 2009 at 10:17 pmhello,
Thank you for the great quality of your blog, every time i come here, i’m amazed.
black hattitude.
by black hattitude November 1, 2009 at 12:10 amme ha gustado mucho!
by carlota January 14, 2010 at 12:57 pm