"La mayor parte de las ideas fundamentales de la ciencia son esencialmente simples, y deben, como regla, ser expresadas en un lenguaje que cualquiera pueda comprender".
A. Einstein

martes, 22 de noviembre de 2011

Greatest Common Factor and Least Common Multiple

Hello everyone,

As we have already studied what GCF and lcm are, I would like you to go over the definition and improve in calculating both, so please, have a look to the following links:

Greatest Common Factor (GCF) is the highest number that divides exactly into two or more numbers.


Read more about GCF
Practice.  More exercises.

Least Common Multiple (lcm) is  the smallest (non-zero) number that is a multiple of two or more numbers.

Read more about lcm
Practice. More exercises.



PLAY A GAME

Practice with PROBLEMS



ALICIA

lunes, 14 de noviembre de 2011

Solid geometry summary

Hi boys and girls,

Here you have the summary I promised, with the six shapes you have to study for the exam.

Download file.

Take care,

ALICIA

domingo, 6 de noviembre de 2011

Sieve of Eratosthenes

The Sieve of Eratosthenes is an ancient method for finding all primes numbers up to a specified number.

It was created by Eratosthenes (275-194 B.C., Greece), an ancient Greek mathematician. Just as a sieve is a strainer for draining spaghetti, Eratosthenes's sieve drains out composite numbers and leaves prime numbers behind. The numbers from 1 to 100 are listed in a table. We will use The Sieve of Eratosthenes to find all primes up to the number 100 by following the directions below.

Directions:
  1. Cross out 1 since it is not prime.
  2. Circle 2 because it is the smallest prime number. Cross out every multiple of 2.
  3. Circle the next open number, 3. Now cross out every multiple of 3.
  4. Circle the next open number, 5. Now cross out every multiple of 5.
  5. Circle the next open number, 7. Now cross out every multiple of 7.
  6. Continue this process until all numbers in the table have been circled or crossed out.
You have just circled all the prime numbers from 1 to 100!

Download presentation


Questions (to be answered as a comment):

1. How many prime numbers are there from 1 to 100?
2. List all prime numbers from 1 to 100.
3. Which number is the only even prime number?
4. An emirp (prime spelled backwards) is a prime that gives you a different prime when its digits are reversed. For example, 13 and 31 are emirps. List all emirps between 1 and 100.

Enjoy it!
ALICIA

Nets

Hi girls and boys,
Here you have a link where you can find the 3D models (also called "nets") for every 3D shape.


If you want to practice associating nets and figures, go to the following site:


ALICIA

Surface area and Volume, part I

Hi all,

these days we have been working in class with surface area and volume of some geometric shapes. I leave you here some links to go over the most important ones:

Platonic solids (tetrahedron, cube, octahedron, dodecahedron, icosahedron)
Pyramids
Prisms
Cylinder, cones, sphere

Remember that you have to present by the end of this week your work including:

1. Description of your shape
2. Net
3. Surface area and volume
4. Examples in real life
5. Problem

(Deadline: friday, 11th of november)


If you want to practice or get some ideas or pictures, you can find more exercises here:
Surface area of a cuberectangular prism, pyramids and conescylinder, cylinder and prism,

Volume of a cuberectangular prism, prism and cylindertriangular prismcone,  pyramid and conecylinderpyramidsphere

Volume and surface area of sphere

Take care,

ALICIA