Expert: Lynn Houston - 5/7/2010

Question
hello pls help me by answering this

#1. 1+5*7-4+9/3-(6+7-8)*3
#2. 5-13-8/2-61+5

thank you

Answer
Ok, so if you don't already know, MDAS is the order of operations.  Multiplication, Division, Addition and Subtraction.  This is the order in which you do the math UNLESS there are parenthesis, then you always start with what's in the parenthesis.  So...

#1. 1+5*7-4+9/3-(6+7-8)*3 take care of parenthesis
1+5*7-4+9/3- 5*3  Do the multiplication
1+35-4+9/3- 15   do the division
1+35-4+3- 15  now the addition
36 - 7 - 15 and finally the subtraction
14

1+5*7-4+9/3-(6+7-8)*3 = 14


#2. 5-13-8/2-61+5  no parens or multiplication, so division is first
5-13-4-61+5  now addition
5-13-4-66
-78

5-13-8/2-61+5 = -78

Look at the last problem to really see the importance of order in the solution of a problem.  Let's just say you went from left to right

5-13-8/2-61+5
-8 - 8/2 - 61 + 5
-12 - 61 + 5
-73 + 5
-68  Totally different answer, so order is important and will become really important once you start algebra and try solving equations.