Simplifying Expressions: 3(7-2.5)-10, 0.80(7 +7.0.05)

[Deondre94]

Hi,

3(7-2.5)-10
7-2.5 = 4.5
3-10= 7
7-4.5 = Answer 3.5?
I think this might be correct
My next problem has me totally stumped 0.80(7 +7.0.05)

I know I will add 7+7 which is 14 and then not sure about the 0.05 and the 0.80. I am ADD so sometimes I am slower than most kids.

I need some help

Thanks,

Deondre

 

[mmm4444bot]

Order of Operations

Hi,

3(7-2.5)-10
7-2.5 = 4.5 ? This is a good start
3-10= 7 ? Red Alert!
7-4.5 = ? Huh?
Answer 3.5? ? This is the correct answer (heh, heh), but I'm concerned about the two prior steps

You are correct to begin inside the parentheses, and that expression equals 4.5

Now replace that expression with 4.5 and continue.

3(4.5) - 10

Do you realize that the parentheses indicate that 3 needs to be multiplied by 4.5?

My next problem has me totally stumped 0.80(7 +7.0.05)

Me, too.

Is that July 0, 2005?

 

[Deondre94]

Re: Simplifying Expressions- Need Help!

Hi,

Thank you for the reply. I see we are both lost on the 2nd. Let me try this again. As I have been working on this one for a long time.

0.80(7+7. 0.05)

After the 2nd 7 there is a big dot and then the 0.05

7+7 needed to be multiplied by the 0.05 but I cant get it to come out right.

Help is needed here

Thank you,

Deondre

 

[mmm4444bot]

Re: Simplifying Expressions- Need Help!

... After the 2nd 7 there is a big dot ...

Hi:

Okay, now I understand.

That big dot is the new multiplication sign for algebra students (or pre-algebra students).

Beginning with algebra, we use the letter x as a symbol to represent a number for which we don't yet have the value or a number that varies in value. So, we can't really use the letter x as a multiplication symbol anymore because then x-squared would be xxx (and your parents would not like that at all).

Usually, the dot is small and centered up-and-down.

\(\displaystyle 7\;+\;7 \cdot 0.05\)

The dot means multiply 7 times 0.05

... 7+7 needed to be multiplied by the 0.05 ...

Nope. Only the second seven needs to be multiplied by the 0.05 -- order of operations says to multiply before adding.

~ Mark