48?2(9+3)
- Thread starter Cheech
- Start date
The way the problem is written is intentionally unconventional. The ÷ symbol is not conventionally used beyond elementary arithmetic, and is certainly not conventionally used when writing on a computer. That's where the ambiguity is (maybe ambiguity isn't the word), although it really shouldn't matter the proper steps of solving a math problem should hold regardless of what symbol is used.
david yurik
AC Members
i understand how 288 is calculated but why do some think its ok to move the (9+3) into the numerator? being located directly next to the 2 puts ( 9+3 ) in the denominator. i dont recall ever being able to arbitrarily move things to where i wanted. maybe i missed that lesson in 4th grade?? (48/2)(9+3) i would agree is 288 but thats not whats written imo. i don't see it as ambiguous at all.
dave
dave
Numbers in parens are calculated first. 288
There is a hierarchy to mathematics.
9+3 is calculated first to arrive at that number. Then it follows in order. 48/2
Simplified it's 24 x 12 or 288
There is a hierarchy to mathematics.
9+3 is calculated first to arrive at that number. Then it follows in order. 48/2
Simplified it's 24 x 12 or 288
2(9+3) is definately conventional. 48/2(12), 48÷2(12), 48/2X12, or 48÷2X12 are all pretty conventional.
I think what throws people off is the brackets and not the division. People will think that the proper solution is multiplying the 2(12) first rather than working on the division .
I said the answer was 2 the first time I read the post. It has been driving me nuts, so I asked my daughter's geometry teacher. She said the answer was 2. This was her reason: 48 divided by 2(9+3) can also be written as 48\ 2(9+3). 9+3=12, times 2 = 24. 48 divided by 24=2. I home school my daughter with the help of Keystone National High School so this problem is important. My 15 year old wants to know who is right.
The geometry teacher is wrong.
Yes, it can be written that way, but it's just another way of writing it. No matter how you write it, the equation and it's answer remain the same. The order of operations always remains the same. Only what is INSIDE parenthesis is performed first. Then, both DIVISION & MULTIPLICATION ARE EQUAL in order of operations, so you go from left to right.
Start with:
48/2(9+3)
Perform ONLY what is INSIDE of the parenthesis and you get:
48/2x12
Now, since we're left with both multiplication & division, you solve FROM LEFT TO RIGHT. You absolutely, positively, DO NOT multiply the 2 x 12 first. This is where everyone is getting confused. So..
48/2 = 24, which leaves you with:
24 x 12, which equals 288.
I'd like to thank Ms. Elder, my 4th grade math teacher...
Yes, it can be written that way, but it's just another way of writing it. No matter how you write it, the equation and it's answer remain the same. The order of operations always remains the same. Only what is INSIDE parenthesis is performed first. Then, both DIVISION & MULTIPLICATION ARE EQUAL in order of operations, so you go from left to right.
Start with:
48/2(9+3)
Perform ONLY what is INSIDE of the parenthesis and you get:
48/2x12
Now, since we're left with both multiplication & division, you solve FROM LEFT TO RIGHT. You absolutely, positively, DO NOT multiply the 2 x 12 first. This is where everyone is getting confused. So..
48/2 = 24, which leaves you with:
24 x 12, which equals 288.
I'd like to thank Ms. Elder, my 4th grade math teacher...
I can now see where the teacher was wrong, but now I have to tell my 15 year old she was right! I'm never gonna live this down.
