Multiplication - Repeated Addition and Arrays

We did it!  We finally looked at multiplication at the end of last week.  Phew!  Two things I shared with students are that multiplication is repeated addition (ex. 2 + 2 + 2 is the same as 3 x 2) and we touched on arrays. I showed them the following real-life arrays and how the orientation of each one results in a different multiplication sentence.  This is VERY important since students will need to be able to illustrate the meaning of a multiplication sentence and we are expected to be strict about how they do this.  The first number in a multiplication sentence represents the number of rows or groups present and the second number is the number of things in each row or group.

Even though 3 x 4 and 4 x 3 equal the same product (12), they do not MEAN the same thing.

When looked at this way, this tray for Ferrero Rocher chocolates shows us a 5 x 3 array.....5 rows and 3 in each row.
5 x 3 = 15


 

If we rotate the same chocolate box it shows us a 3 x 5 array.....3 rows with 5 in each row.
3 x 5 = 15

Likewise, an egg carton looked at this way shows a 6 x 2 array.....6 rows with 2 in each row.
6 x 2 = 12

Rotated the other way, the egg carton shows us a 2 x 6 array .. 2 rows with 6 in each row.
2 x 6 = 12

This week, please encourage your child to look around the house to find examples of arrays.  I can see one right now on the keypad of the phone beside my computer!  How many different examples can your child find?  Encourage her or him to name the array according to the examples given above.

Also, even though we're venturing into multiplication, please don't forget about addition and subtraction, particularly with regrouping.  A couple of problems a day will help to keep them sharp!

I haven't added any new websites this week.  There are some games available that involve arrays, but we haven't done enough yet at school to be ready for those, so please just continue to encourage your child to practice addition/subtraction facts, place value, and measurement.

Thanks and have a great first full week of February!