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 Discussion: All Topics Topic: Order of Operations (BOMDAS)

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 Subject: RE: Simplify the OOO using terms Author: lukus Date: May 9 2006
On Mar 24 2003, Mathprof wrote:
> My students never have problems with Order Of Operations because
> they are told to split all expressions into terms.

A term starts
> with a + or - that is NOT in parentheses.

Thus, to evaluate 5*4
> +3(6-8)+3^2-8+5

the student writes 5*4   +3(6-8)   +3^2   -8   +5
> Each term is evaluated    +20  -6  +9  -8  +5

The reults are now
> combined according to the rules of Algebra.   +34 -14 = +10
!!!WRONG***WRONG!!!
> Students discover that the individual terms can be evaluated in ANY
> order.

Creating terms is particularly important with expressions
> such as  10-3(2) where students tend to write 7(2)=14

Of course,
> all this assumes that students know how to oparte with signed
> numbers.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+34 -14 = +20

EASIER TO THINK OF BOMDAS THIS WAY:

BO MD AS
BO MD SA
BO DM AS
BO DM SA

AS LONG AS YOU KNOW THAT "M" & "D" ARE INTERCHANGEABLE AND "A" & "S" LIKEWISE,
BUT "M" OR "D" MUST BE PERFORMED BEFORE "A" OR "S".

IN "MD" IT DOES NOT MATTER WHICH (M OR D) IS DONE FIRST
EX 5x4÷2=? .....20÷2 = 5x2 !

LIKEWISE FOR "AS"
EX 5+4-2=? .....9-2 = 5+2