Order of operations -- help me

[Anonymous]

5th grade math:

"simplify the expression below" (I'm using a "^" to show an exponent b/c I don't know how to do the superscript font)

1. 6^2 - 4* (7-4)
I thought it would be 36-4 * (7-4) ----> 32 x 3


2. 5^2 - 4* (5-3)
I thought ti would be 25 - 4 x (2) ----- 21 x 2 = 42
But DC got it wrong. The other options for answers were (a) 2, (b) 8, or (c) 17.

Help.

???

[Anonymous]

PEMDAS.

http://www.mathsisfun.com/operation-order-pemdas.html

[Anonymous]

Anonymous wrote:

1. 6^2 - 4* (7-4)
I thought it would be 36-4 * (7-4) ----> 32 x 3

It's 36 - 4(3) = 36 - 12 = 14

[Anonymous]

Anonymous wrote:

2. 5^2 - 4* (5-3)
I thought ti would be 25 - 4 x (2) ----- 21 x 2 = 42
But DC got it wrong. The other options for answers were (a) 2, (b) 8, or (c) 17.

25 - 4(2) = 25 - 8 = 17

You multiply before you do the subtraction.

[Anonymous]

2 is c

[Anonymous]

My dear aunt sally == (multiply, divide) then (add, subtract)

#1 is:

(6^2) - (4 * (7 - 4))
36 - (4 * (7 - 4))
36 - (4 * 3)
36 - 12
24

[Anonymous]

OP here, Does it matter in (1) that the 4 is not right next to the parenthesis? It's not 6^2 - 4(7-4). It was clearly written with a multiplication sign b/t the 4 and the parenthetical. I would have done it like 21:37 wrote if it had been 4(7-4). It's a bit confusing.

[Anonymous]

Solve the parentheses first. Then do the multiplication. Then do the subtraction.
So it would be 6^2-4(3)=36-12=24

Next one is 5^2-4(2)=5^2-8=25-8=17

[Anonymous]

Anonymous wrote:5th grade math:

"simplify the expression below" (I'm using a "^" to show an exponent b/c I don't know how to do the superscript font)

1. 6^2 - 4* (7-4)
I thought it would be 36-4 * (7-4) ----> 32 x 3


2. 5^2 - 4* (5-3)
I thought ti would be 25 - 4 x (2) ----- 21 x 2 = 42
But DC got it wrong. The other options for answers were (a) 2, (b) 8, or (c) 17.

Help.

???

The mistake you made was subtracting before multiplying - in both problems.
First problem - start with the parenthesis. Now, you have 6(squared) - 4 *3.
Now, do the exponent. Now, you have 36 - 4 * 3.
NOW, you multiply first because multiplication comes before subtraction. 36 - 12
The PEMDAS helps, but if you have BOTH addition and subtraction in a problem or BOTH multiplication and division in a problem, then you do the arithmetic from left to right.

[Anonymous]

Anonymous wrote:OP here, Does it matter in (1) that the 4 is not right next to the parenthesis? It's not 6^2 - 4(7-4). It was clearly written with a multiplication sign b/t the 4 and the parenthetical. I would have done it like 21:37 wrote if it had been 4(7-4). It's a bit confusing.

It doesn't matter. It's exactly the same. 4(7-2) is exactly the same as 4x(7-2).

[Anonymous]

Anonymous wrote:OP here, Does it matter in (1) that the 4 is not right next to the parenthesis? It's not 6^2 - 4(7-4). It was clearly written with a multiplication sign b/t the 4 and the parenthetical. I would have done it like 21:37 wrote if it had been 4(7-4). It's a bit confusing.

No that does not matter. Putting the number next to the parenthesis is just shorthand for multiply. The multiplication symbol (asterisk, x, etc.) is optional.

[Anonymous]

Thanks for all of the help.

Are you smarter than a 5th grader -- for some of you -- yes! For me, no!

[Anonymous]

Anonymous wrote:OP here, Does it matter in (1) that the 4 is not right next to the parenthesis? It's not 6^2 - 4(7-4). It was clearly written with a multiplication sign b/t the 4 and the parenthetical. I would have done it like 21:37 wrote if it had been 4(7-4). It's a bit confusing.

No, both mean to multiply - whether there is a multiplication sign or if the number is directly outside the parenthesis. Generally, kids do not start learning 4(3-1) until 5th or 6th grade or so. Up until then, they use the multiplication sign.

[Anonymous]

Anonymous wrote:Thanks for all of the help.

Are you smarter than a 5th grader -- for some of you -- yes! For me, no!

OP, don't feel bad, you sound like my mom, she is very smart, has a degree in philosophy, reads book I cannot even understand the title of, but does not understand math at all, she can barely add and subtract. it does not mean she is not smart. I never let her help me with math though, even in elementary school it was clear to me that I was better off doing it by myself

[Anonymous]

straightforward:

http://lmgtfy.com/?q=order+of+operations