Multiplication & Division and Book Trailers

12 Feb

Right now both classes are focusing on multiplication and division through the lens of division.    The learning goal is to deeply understand the concept that they are inverse operations, they “undo” each other.  This is a critical concept for math.  We will be exploring this concept with manipulative such as colour tiles and through rich problems.

We started with a simple problem of splitting up brownies between friends.  We have 20 brownies and we want to split them equally between 5 friends.  How many brownies do we have?  I can be difficult to a student to translate that question into a division expression so we used the tiles.  Each student had 20 tiles to represent the brownies.  Most sorted them into 5 groups and found that each person gets 4 brownies.  Once the tiles are split up we can see the multiplication expression 5 x 4 = 20   5 people each get 4 brownies or 5 groups of 4 = 20.  Then we talked about what 4 x 5 means – 4 groups of 5.  Although the product is still 20, it’s slightly different because there are 4 groups of 5 instead of 5 groups of 4.  One might wonder why this is an important distinction – because they need to understand division.  If 20 brownies are divided between 5 people they each get 4 but if their divided by 4 people, they each get 5.  There is a difference.  A common error for children is to put the numbers in the wrong order for divison, for example:  5 divided by 20 = 4.  It’s important for them to understand that the dividend (20) is the total amount, the divisor (5) is the number of groups and the quotient is the number in each group.

The brownies are divided into 5 groups so each person gets 4 brownies.

The brownies are now divided into 4 groups so each person gets 5 each.

Today each class worked in pairs to solve a division and were asked to prove their answer was correct (use multiplication to prove their division was accurate).  Tomorrow we will share strategies and I will post different methods here.

Book Reports

Both classes have been asked to read a novel and have it finished by February 18th in order to create a book report.  The grade 5s will all be doing book trailers, like a movie trailer but about a book.  The grade 4s will have several creative choices to choose from, more information to come.  All the work (other than the reading) will be done in class.   Here is an example of a book trailer for the excellent book Wonder.