When simplifying this problem, would you divide or add first?

Question

3. Simplify: 9 – 2[7 – 17] ÷ (-5)

Which one:

9-2(-10) ÷ (-5)
9-2(-10) ÷ (5-5)
9+20 ÷ (-5) <-- add first?
29 ÷ (-5)
= 29/5 or 5 4/5

OR:

9 – 2[7 – 17] ÷ (-5)
= 9 – 2[-10] ÷ (-5)
= 9 + 20 ÷ (-5)
= 9 – 4
= 5

Answer 1

Always remember to Please Excuse My Dear Aunt Sally... or that is to do Perenthesis, Exponents, Multiply, Divide, Add, Subtract, in that order.

For your problem 9-2[7-17]/-5, you would first do whatever is in the square brackets because those are essentially parenthesis. So you get
9-2[-10]/-5

Now you have no exponents so you skip to multiplying. The only multiplying you have here is the -2 times the -10. This gives you
9+20/-5.

Next comes divide,so
9-4

Then it is a very simple equation and you are left with 5.

Answer 2

Always simplify expressions separated by grouping symbols first... parentheses, brackets, braces, a fraction bar.

9 – 2[7 – 17] ÷ (-5)
= 9 – 2[-10] ÷ (-5)

Exponents and roots should be evaluated next, but there aren't any in this problem.

Multiplications and divisions come next, in order from left to right.
9 – 2[-10] ÷ (-5)
= 9 + 20 ÷ (-5)
= 9 + (-4)

Additions and subtractions come last, again, in order from left to right.
9 + (-4)
= 5

Answer 3

The second second method is correct.
Go according to the convention BODMAS which means Brackets of Division, Multiplication Additon, Subtraction.
First divide then add.

Answer 4

The second way is right.

Multiply/Divide before add/subtract outside the parenthese.

Answer 5

9 - 2(7 - 17) / -5

9 - 2(-10) / -5
9 + 20 / -5
9 - 4
5

The second one.

Answer 6

The second one is corect

Please click on the URlL below for additional information concerning order of operation.

math.about.com/library/weekly/aa040502a.htm

Answer 7

Use your second solution. The brackets around the -5 are not considered brackets as in "BEDMAS", they are simply there to make the equation easier to read.

Answer 8

Brackets first, then powers, then division or multiplication, then adding or subtracting. The last answer is correct.

Answer 9

The 1st way; always solve what's in the parentheses first

Answer 10

Division always first