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UNIT 5. DECIMAL NUMBERS

1.- DECIMAL NUMERAL SYSTEM

1. Read the following paragraph

deci02.jpg

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

decimas.jpg
Just do “Colorea”
centesimas.jpg
Just do “Ábaco 1”
milesimas.jpg
Just do “Ábaco2”
Now, do these Exercise 1 and exercise 2

transformaciones.jpg


2.- REPRESENTATION OF DECIMAL NUMBERS ON A LINE

1.- Try the following interactive exercise. Just do “La recta real”

linea.jpeg

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.

0.459 compared with 0.495

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

ordering.jpeg

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).
3/4 = 3 divided by 4 = 0.75
  • A decimal fraction with one decimal place is written as tenths.
0.1 = 1 divided by ten or one tenth
  • A decimal fraction with two decimal places is written as hundredths.
0.15 = 15 divided by ten or fifteen hundredths
  • A decimal fraction with three decimal places is written as thousandths
0.053 = 53 divided by 1000 or 53 thousandths

2.- Now, practice with the following exercise but only pages 12 and 13

fraccion.png

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

suma.jpeg

resta.jpeg

multiplicacion.jpeg

division1.jpeg

division2.jpeg

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/decimalsk-3/rounding-decimals2-3.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

http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/comparing/comparingall3/worksheet13.shtml

http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/comparing/comparingall3/worksheet15.shtml

4. Now check the answers

http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/comparing/comparingall3/worksheet14.shtml

http://www.bbc.co.uk/skillswise/numbers/fractiondecimalpercentage/comparing/comparingall3/worksheet16.shtml

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

 

4 comments

  1. ¡¡una calculadora muy completa y muy chula!!


  2. Great site, how do I subscribe?


  3. hello,

    Thank you for the great quality of your blog, every time i come here, i’m amazed.

    black hattitude.


  4. me ha gustado mucho!



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