Class Topics: 10.21.11

In EDM today, we worked with algebraic expressions that used two variables which is an increase in difficulty from yesterday.   We analyzed several special cases looking for similarities so we could develop our appropriate algebraic expression.
Special Case:                                  Algebraic Expression/General Pattern:
(5 * 2) + (5 * 6) = 5 * (2 + 6)        (5 * d) + (5 * c) = 5 * (d + c)
(5 * 3) + (5 * 7) =  5 * (3 + 7)
(5 * 8) + (5 * 9) = 5 * (8 + 9)


When converting a special case to an algebraic expression, we are looking for those things (numbers and operations) that don't change from example to example.  (5 * _ ) + (5 * _ ) = 5 * ( _ + _ )  What we notice is that 5 remains constant throughout all three cases as well as the operations of multiplication and addition.  Also, there are three pairs of parentheses, two on the left of the equal sign and one on the right.  Then we substitute those things that change throughout each case with a variable.  

In Pre-Algebra today, we used our dry erase boards to work on dividing rational numbers.  The video below helps model the skill from today.