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View Full Version : Can anyone help me figure out a math problem so I can help my son ?

TurdFerguson
09-21-2012, 11:19 PM
My son has an extra credit page in his 6th grade math class. They have been working on order of operations. I always go through his work before he turns it in and if he has a problem wrong, I let him know so he can redo it. There are 5 problems and I've been able to figure out 4 of them but this one just doesn't work out for me.

This is the problem:

__ x __ / 10 + __ x __ / 4 - __ = 6

These are the numbers that must be used only once to fill in blanks

(2,5,7,8,9)

The closest I've been able to come is 7.

Can anyone help me ?

Wickabee
09-21-2012, 11:32 PM
__ x __ / 10 + __ x __ / 4 - __ = 6
These are the numbers that must be used only once to fill in blanks
(2,5,7,8,9)

If I remember my grade 8, which I likely don't (hahaha...sigh) You've got it right but the wrong order. You're supposed to do division and multiplication before addition and subtraction, which means you do both "halves" of the equation independently, then do the addition, then the subtraction.

2x5=10 7x8=56
10/10=1 56/4=14

14+1=15

15-9=6

So you've posted the numbers in the right order, looks like you were doing the steps in the wrong order. I got 7 my first try too.

drtom2005
09-21-2012, 11:33 PM
2x5/10=1+7x8/4=14-9=6

TurdFerguson
09-22-2012, 12:02 AM
If I remember my grade 8, which I likely don't (hahaha...sigh) You've got it right but the wrong order. You're supposed to do division and multiplication before addition and subtraction, which means you do both "halves" of the equation independently, then do the addition, then the subtraction.

2x5=10 7x8=56
10/10=1 56/4=14

14+1=15

15-9=6

So you've posted the numbers in the right order, looks like you were doing the steps in the wrong order. I got 7 my first try too.

OMG, thank you so much ! I thought that was the right order for the numbers, especially with /10 part. I was going crazy knowing I wasn't doing something in the right order. There was one earlier in the week that I looked at forever and finally just let it go and checked all of the others. The next time I looked at it, I could just see it. I think I was doing what my son does from time to time and that's try to multiply first and then divide instead of going from left to right.

2x5/10=1+7x8/4=14-9=6

Thank you as well.

Wickabee
09-22-2012, 03:21 PM
I think I was doing what my son does from time to time and that's try to multiply first and then divide instead of going from left to right.

I definitely recall math teachers telling me that is such a common mistake it's on the level of a brain fart, haha.

will22clark
10-23-2012, 07:26 AM
2x5/10=1+7x8/4=14-9=6

2x5/10=1+7x8/4=15-9=6

TurdFerguson
10-23-2012, 07:51 AM
2x5/10=1+7x8/4=15-9=6

Umm, this was solved over a month ago....

will22clark
10-23-2012, 08:56 AM
:p: I figured now or never & why not correct that minor error that I spotted.... At the same time testing my own skills for fun.