Monday, 24 October 2016
Friday, 22 January 2016
Mathematical Operations
Bonjour!
We are working on our mathematical operations right now in Grade 3. We often start our class with a warm-up where one student will write a three-digit number 'answer' on the board, and the students are responsible for sharing a 'question' that will equal that number. Students are able to use whatever operations they like (plus, minus, times, and dividing), and lately I've been asking them to use at least two different ones.
Students are starting to use dividing and multiplication more and more in their questions, which is great. Feel free to have your students give you some ways to get to any three-digit number using plus, minus, times, and dividing. Here are some examples for 405 and 955:
We are also working this year towards being able to add and subtract three-digit numbers. We are learning some mental strategies for subtraction right now, and we will be learning the traditional algorithm as well eventually.
We are working on our mathematical operations right now in Grade 3. We often start our class with a warm-up where one student will write a three-digit number 'answer' on the board, and the students are responsible for sharing a 'question' that will equal that number. Students are able to use whatever operations they like (plus, minus, times, and dividing), and lately I've been asking them to use at least two different ones.
Students are starting to use dividing and multiplication more and more in their questions, which is great. Feel free to have your students give you some ways to get to any three-digit number using plus, minus, times, and dividing. Here are some examples for 405 and 955:
We are also working this year towards being able to add and subtract three-digit numbers. We are learning some mental strategies for subtraction right now, and we will be learning the traditional algorithm as well eventually.
Friday, 8 January 2016
Pairs that make 100
Bonjour! Et Bonne Annee! Happy New Year!
This week we have been working with our "Quel est la question?" routine at the start of most math classes. One student is responsible for picking a 3-digit number between 100 and 999. They write it on the board and the other students need to come up with at least one question that will give that number as an answer. I'm asking students to consider using addition, subtraction, and multiplication in their questions.
For example number 184
10x10 + 80 + 4
200 - 16
100 + 20 + 20 + 20 + 20 + 4
184 x 1
etc
Also we are working on finding matching numbers that add up to 100. In partners, one partner picks a number between 0 and 99. The other partner must write the other number that makes the total add up to 100. I'm asking the students to try doing this mentally, and then checking their answers afterwards using one of our RekenReks, the 100's chart, a number line, or whatever tool they would like to use.
For example:
36 + 64
71 + 29
18 + 82
The main idea is that the ONES need to add up to 10, while the TENS column add up to only 9, since the 10 ones will add one extra 'ten' for the sum. Here is the 100-bead Rekenrek that can be used to check 36 + 64:
These pairs can be practiced at home, and extended to pairs that add up to 1,000 as well.
This week we have been working with our "Quel est la question?" routine at the start of most math classes. One student is responsible for picking a 3-digit number between 100 and 999. They write it on the board and the other students need to come up with at least one question that will give that number as an answer. I'm asking students to consider using addition, subtraction, and multiplication in their questions.
For example number 184
10x10 + 80 + 4
200 - 16
100 + 20 + 20 + 20 + 20 + 4
184 x 1
etc
Also we are working on finding matching numbers that add up to 100. In partners, one partner picks a number between 0 and 99. The other partner must write the other number that makes the total add up to 100. I'm asking the students to try doing this mentally, and then checking their answers afterwards using one of our RekenReks, the 100's chart, a number line, or whatever tool they would like to use.
For example:
36 + 64
71 + 29
18 + 82
The main idea is that the ONES need to add up to 10, while the TENS column add up to only 9, since the 10 ones will add one extra 'ten' for the sum. Here is the 100-bead Rekenrek that can be used to check 36 + 64:
Wednesday, 9 December 2015
Grade 3: polygons and right angles
Bonjour! We have started a unit on Geometry and are learning about polygons and right angles. The polygons are shapes that have many sides. One big idea is that the polygons are named for the number of sides they have, regardless of what they look like.
Polygons (Les Polygons)
triangle (un triangle) - 3 sides
quadrilateral (un quadrilatère) - 4 sides (square, rectangle, others)
pentagon (un pentagone) - 5 sides
hexagon (un hexagone) - 6 sides
heptagon (un heptagone) - 7 sides
octagon (un octogone) - 8 sides
These are the main ones we will focus on in this unit. Please review these terms at home for practice.
Right Angles (les angles droits)
We are learning about what angles are, and how to tell if an angle is a right angle or not. At this point, we are NOT using degrees for measuring (i.e. a right angle is 90 degrees). This is how I've explained it so far:
-an angle is a corner of a shape
-a right angle is a corner that is EXACTLY like the corner of a square
-if it's not exactly the same, the corner can be SMALLER or BIGGER than a square
If you see examples of right angles around the house or town, please point these out to your student, as this concept is still very new.
This week we have been working with geoboards to try to make the different polygons and trying to make them with as many or as few right angles as possible. Geoboards are plastic square boards with pegs in them, that elastic bands fit around to make the polygon shapes. Here is a photo of one, the example has a pentagon on it (5 sides), and contains three right angles (corners that are the same as the corner of a square).
In this shape, the top left, bottom left, and bottom right corners have the right angles. The other two corners are 'bigger' than a right angle because in you put a square in the corner, there will be extra space left over.
Happy shape and angle hunting!
Polygons (Les Polygons)
triangle (un triangle) - 3 sides
quadrilateral (un quadrilatère) - 4 sides (square, rectangle, others)
pentagon (un pentagone) - 5 sides
hexagon (un hexagone) - 6 sides
heptagon (un heptagone) - 7 sides
octagon (un octogone) - 8 sides
These are the main ones we will focus on in this unit. Please review these terms at home for practice.
Right Angles (les angles droits)
We are learning about what angles are, and how to tell if an angle is a right angle or not. At this point, we are NOT using degrees for measuring (i.e. a right angle is 90 degrees). This is how I've explained it so far:
-an angle is a corner of a shape
-a right angle is a corner that is EXACTLY like the corner of a square
-if it's not exactly the same, the corner can be SMALLER or BIGGER than a square
If you see examples of right angles around the house or town, please point these out to your student, as this concept is still very new.
This week we have been working with geoboards to try to make the different polygons and trying to make them with as many or as few right angles as possible. Geoboards are plastic square boards with pegs in them, that elastic bands fit around to make the polygon shapes. Here is a photo of one, the example has a pentagon on it (5 sides), and contains three right angles (corners that are the same as the corner of a square).
In this shape, the top left, bottom left, and bottom right corners have the right angles. The other two corners are 'bigger' than a right angle because in you put a square in the corner, there will be extra space left over.
Happy shape and angle hunting!
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