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Order of Operations By Mr. Walker The Expression We need to simplify this expression down to one number (find the answer). 3 25 +(3x5)-2 5 But where do we start? There is a certain order we need to follow when we simplify this expression, or we will get the wrong answer. This is called… Order of Operations It goes like this… Going left to right (like when reading) • Do anything in Parentheses • Start over and do any Exponents • Start over and do any Multiplication and Division • Start over and do any Addition and Subtraction Definitions Parentheses are… 3 25 5 +(3x5)-2 ( ) Exponents are … Powers and Roots 2 3 16 In this problem 2 has a power of three, which means you should multiply 2 by itself three times: 2x2x2 Multiplication and Division are … X 25 is the same as saying 25 5 Addition and Subtraction are… + - 5 How Do I Remember All This? Easy… Please Excuse My Dear Aunt Sally Dear Aunt Sally P had aEvery bad M day, D soAplease S excuse her. It all started when shex burnt her a u tongue i d on her u hot coffee. Then on the way Whilebshe was r to work p her car l died. v d walking the rest e of theo way to work t i a car i drove t by and splattered hernwith mud. n Wheni she s finally t gotr to work her boss fired her tfor being e late. Since p i she idid not a have a job anymore she hstarted nwalking home l o ando found c a quarter on the sidewalk but soon e near a t tree. ‘Great,’ i n she n thought t found out thatsit was super-glued While she s c to the sidewalk. i was looking down at the quarter e a a bee stungoher and she stood up so fast s that she forgott the tree branch n right above her head. BONK! Just then a 7 year old boy bumped o into her because he was reading n a comic book as he walked. When he looked up to say ‘Excuse me,’ this is what he saw… So … Please Excuse My Dear Aunt Sally Step by Step ‘P’ 3 3 2525 +(3x5)-2 +15-2 55 Please Excuse My Dear Aunt Sally P a r e n t h e s e s (3x5) is 15, so put the 15 in the spot of the (3x5) You most likely will not have to deal with this step in 4th grade. Step by Step ‘E’ 3 25 +15-8 +15-2 5 Please Excuse My Dear Aunt Sally E x p o n e n t s 3 2 Is the same as 2x2x2 2x2=4 x2 again is 8 3 So replace the 2 with the 8 Step by Step ‘M’ & ‘D’ 25 +15-8 5+15-8 5 Please Excuse (My Dear) Aunt Sally M u l t i p l i c a t o n D i Do any multiplication and division as you read left to right v i There is nothing to multiply so do the division. s i 25 is the same as saying 25 5 o 5 n 25 divided by 5 is 5. So replace the 25 with the 5 5 Step by Step ‘A’ & ‘S’ 5+15-8 20-8 12 Please Excuse My Dear (Aunt Sally) A d d i t i o n S u b t r a c t i o n You are done! Do any addition and subtraction as you read left to right Add the 5+15 to get 20 Take out the 5+15 and put the 20 in that spot Subtract the 8 from the 20 and get 12 1 10 20 -8 12 borrow Take away the 20-8 and put the 12 Let’s Try One Together Remember Please Excuse My Dear Aunt Sally Simplify this expression 5+(3x4)- 36 Parentheses: (3x4) = 12 6 5+12- 36 6 Exponents: None-Skip 5+12- 36 Multiplication: None-Skip Division: 36 divided by 6 = 6 Addition: 5+12=17 Subtraction: 17-6=11 6 5+12- 36 6 5+12-6 17-6 11 Try These On Your Own 2+(4x9)- 50 5 Answer 28 56 7 +2x(3x9)-60 Answer 4x(1+7)-24 2 Answer 3 24 3 3 -20+(45 +5)-7 9 Answer 10 For Fun Make Up Your Own Aunt Sally Story Please Excuse My Dear Aunt Sally because…