Decimals

Hi Grade 5s,

We began our unit on decimals today.  We learned that decimals represent part of a whole number and we found examples of decimals we use everyday, like in money and in measuring with rulers.

When we talk about money, we talk about dollars and cents.  We discovered that "cent" means 100--we need 100 cents to make a dollar (just like we need 100 years to make a century).  We realised that $1.23 is a decimal number, and we can talk about it in different ways:

1 dollar and 23 cents

1 whole dollar and 23 cents towards another whole dollar

1.23

1 and 23/100  (one and twenty-three hundredths: another way to write a fraction--imagine the 23 is above the 100)

We then looked at a ruler.  If we were asked to measure 5.4 cm, we know that the 5 represents 5 whole centimetres, and the .4 represents 4 milimetres.  We need 10 milimetres to make 1 whole centimetre.  We can talk about this decimal number in different ways, too:

5 centimetres and 4 milimetres

5 whole centimetres and 4 milimetres towards another whole centimetre

5.4

5 and 4/10  (five and four tenths)

We also practised drawing decimal numbers using base ten blocks.  We began by using a hundreds flat to equal 1 whole.  Because we need 10 tens rods to make a whole, the rods represent tenths.  We need 100 unit cubes to make a whole, so the unit cubes represent hundredths.

Here's how we can show 4.62:

4 and 62/100 (four and sixty-two hundredths)

Questions? Post them here!

-Ms. Lewis

Geometry Test

TGIF, Grade 5s!

Today, I gave you your study sheets for Tuesday's test on our recent geometry unit.  Here's what the study sheet said:

We will be having a test on what we’ve been learning about whole numbers. Our test will be on Tuesday, November 24th.
Make sure you know how to:

• name triangles based on the length of their sides (e.g., equilateral, isosceles, scalene)

• name triangles based on their angles (e.g., right angle triangle, obtuse triangle, acute triangle)

• measure the angles of triangles with the use of a protractor

• draw an angle when given a measure (e.g., draw a 45° angle)

• construct a triangle given measurements of sides and/or angles (e.g., construct triangle ABC, with angle A measuring 25°, angle B measuring 80°, and the length of AB measuring 42mm)

• recognize which net creates which 3D solid

• create a net for a 3D solid (e.g., make a net for a triangular prism)

Are YOU ready?
 
Have a great weekend!
 
-Ms. Lewis.

Constructing Nets

Hi Grade 5s,


Today in class we talked about nets. Remember that to create a net, we need to find out how many faces a figure has, and what shape those faces are.
For example, I could make a net of this pentagonal prism:

First, I would count the faces and find that there are 7 faces (2 bases, 5 faces around). 5 of those faces are rectangles, and the other two faces are pentagons.

The net would look this this:

Find a solid figure around your house. See if you can figure out how you could create it with a net. Prize tomorrow for whoever posts their net here first.

Yay nets!
-Ms. Lewis.

Naming and Sorting Polygons by Angles

Happy Monday!

Today in class we began to talk about how to name triangles based on their angles.  We remembered that:

• right angles are 90°
• acute angles are less than 90°
• obtuse angles are greater than 90°

We learned that we can measure the three angles (tri-angle...remember?) of a triangle to determine whether it is a right angle triangle, an acute angle triangle, or an obtuse angle triangle.  The rule is:

• right angle triangles have one 90° angle
• acute angle triangles have all 3 angles less than 90°
• obtuse angle triangles have one angle greater than 90°

Remember: you can only have an acute triangle if all 3 angles are less than 90°.

Regular polygons are polygons (closed shape, at least 3 sides) that have all sides the same length, and all equal angles.  Irregular polygons have sides of different lengths, and different angles.

SUPER TERRIFIC BRAIN-BUSTING QUESTION:
WHAT KIND OF TRIANGLE IS A REGULAR POLYGON?  EXPLAIN YOUR ANSWER!
(First person to post the answer on the blog wins a prize in class tomorrow!)

See you tomorrow!

-Ms. Lewis.

Measuring Angles

Hi Grade 5s,


Today we began measuring angles using protractors. Don't worry if you're still trying to get the hang of it--it takes practice and patience.

I found a great interactive activity at mathisfun.com where you can use a virtual protractor to measure angles.

Try it out!

http://www.mathsisfun.com/geometry/protractor-using.html
-Ms. Lewis.

Geometry Definitions

Hello you lovely learners!

For homework tonight, you had to find the definitions for the following geometry terms:

• equilateral triangle
• isosceles triangle
• scalene triangle
• pentagon
• hexagon
• octagon
• parallelogram
• trapezoid

You can post your definitions straight to the blog as a comment, if you like.  Just remember to include your name.

See you tomorrow!

-Ms. Lewis.

Triangles, Triangles, Triangles!

Happy Monday!

Today, we began our geometry unit by looking at the 3 different kinds of triangles: equilateral, isosceles, and scalene. 

Let's take a closer look at each:

Equilateral - We recognized that the word "equilateral" sounds a lot like "equal", which means the same.  We are so smart that we figured out that an equilateral triangle is a triangle with all 3 sides the same length.

Isosceles (eye-saw-so-leez) - We learned that an isosceles triangle is one with two sides that are the same length.

Scalene (skay-leen) - We figured that if an equilateral had 3 sides of the same length, and an isosceles had 2 sides of the same length, then a scalene triangle must have 3 sides of different lengths. 

We're so smart...

See you tomorrow!

-Ms. Lewis.