can you please break this very simple problem:

4 X 4 + 4 X 4 + 4 - 4 x 4 =

I am old and I forget stuff. :) Thank you!

can you please break this very simple problem:

4 X 4 + 4 X 4 + 4 - 4 x 4 =

I am old and I forget stuff. :) Thank you!

Tutors, please sign in to answer this question.

Order of Operations

PEMDAS

Parenthesis

Exponents

Multiplication

Division

Addition

Subtraction

all problems are read left to right

step 1 Check for grouping symbols like parentheses

none present

step 2 check for exponents, There are none as written but note: any thing multiplied by itself is by definition exponential: a*a=a^2

the symbol ^ means to the power of so we pronounce this a to the power of 2 or a squared.

the 2 comes from the fact that there are 2 a terms being multiplied.

another way to write this equation is

4^2+4^2+4-4^2

so we simplify the exponents:

4^2=16

so

16+16+4-16

you can do this 2 ways

1. add then subtract

16+16= 32+4 = 36-16=20

2. by the commutative property of addition you can commute one of the +16 terms to be next to the negative 16, if you look at it like everything is addition and you are adding a negative to a positive instead of subtracting.

so you are actually re-writing the equation as

16+4+16-16

a-a = 0

any number minus itself equals zero

16+4+0 or 16+4 = 20

or you can look at it this way 4 x 4 = (4+4+4+4)

so (4+4+4+4)+(4+4+4+4)+4-(4+4+4+4) this is really 4*9-16=36-16=20.

Math is how you look at it. There are so many ways to solve one problem. as long as you play by the rules and you don't "cheat" :D it is a great way to get students to think outside the box, problem solve and critically think. these are all vitally important skills in life. I hope you liked my explanation of question. If you are interested in tutoring, please look me up on wyzant, http://www.wyzant.com/tutors/TheTechTutor.

Thanks for your time.

Sincerely,

Ian F.

The TechTutor

Remember to keep with order of operations! Multiply before addition or subtraction.

4x4+4x4+4-4x4 multiply all first

16+16+4-16 "cheat" 16-16=0

16+4=20

You're right! It's very simple.

4 X 4 + 4 X 4 + 4 - 4 x 4 = 16+16+4-16 = 20

I suggest you use a calculator if you want the final answer fast, not the explanation and the method

4x4+4x4+4-4x4 = 4^{2}+ 4^{2}+4-4^{2 }= 16+4=20 [multiply first then add]

Dana R.

English/Math SAT PrepTutor with PhD

Lynbrook, NY

4.8
(85 ratings)

Alex C.

Harvard/MIT Finance and Statistics Tutor

Fort Lee, NJ

5.0
(223 ratings)

Steven M.

Premium Test Prep and Subject Tutor - New York City UWS

New York, NY

5.0
(247 ratings)

## Comments

I'm just a 30+ year veteran home school mom, age 57 but I'm pretty sure this is correct after all those years teaching algebra, lol:

Order of Operations:

4x4+4x4+4-4x4=

Multiplication and Division, left to right:

(4x4)+(4x4)+4-(4x4)=

16+16+4-16=

Then Addition and Subtraction, left to right:

32+4-16=

36-16=20