Friday, November 9, 2012

Properties of Multiplication

        We have been exploring multiplication and division for several weeks.  This week our focus was on the properties of multiplication.  We worked with the Associative Property of Multiplication, Identity (One) Property, Zero Property and the Distributive Property.  We were doing great until it came to decomposing of a factor piece of the Distributive Property.  I have a list of the steps we followed: 
Example:  5 x 13

Strategy Steps: 
1.    Decompose or expand one of the factors into two addends.  For example 13 can be broken into 0+13, 1+12, 2+11, 3+10, 4+9, 5+8, or 6+7.
2.    Choose numbers that are easy for you to multiply.  10 + 3 would be a great choice! 
3.    Then distribute 5.
                      5 x (10 + 3)
                 (5 x 10) + (5 x 3)
                     50     +     15

This was a lot harder than I thought it would be for some of my kiddos.  So . . . any suggestions? I am hopeful that with more practice my students will get this strategy but after our thirty minute work period not quite half of my class had a solid grip on this strategy. 


  1. I can't believe 3rd grade is now required to use the distributive property. Our school uses open arrays starting in 3rd grade, then they use them in 4th and 5th. they could break the number into 10s place then ones place, and see how the multiplier would "look"distributed. Hope that helps!


  2. Thank you Emily! This is a great idea to have my kiddos break up their arrays. I will definitely use this on Tuesday.