I am really struggling with MM!

[Juniper]

I went ahead and purchased MM when it was recently on sale. Dd is in the 5th grade book and I am starting to wonder if she needs a calculator.

 

Here was the problem:

 

Mary jogs 7/12 miles each day, five days a week. Calculate how many miles she jogs in a 52-week year.

 

Dd worked this problem by multiplying 5*7/12=35/12

 

then 52*35/12

 

then 1820/12

finally 151.6 miles in the year.

 

The solutions manual has it as

7/12 × 5 × 52 = 151 2/3 miles

 

I cannot figure out how MM works this problem. I see that the answers are very close, but I am struggling with explaining how this was worked to dd.

 

Thanks.

Edited May 2, 2012 by Juniper

[wapiti]

Your dd did long division and left off the repeating decimal (6), rather than reducing the fraction. Her only error is in leaving the line off over the 6.

 

1820/12 reduces to 455/3.

[ssavings]

1820/12 is right. Don't convert to decimal, just simplify the fraction.

 

1820/12 = 151 8/12 = 151 2/3

[momto2Cs]

It looks like the same answer to me, only one is expressed as a fraction, and one as a decimal. So your daughter reduced it to a decimal, and the author left it as a fraction.

 

I could be mistaken, but offhand that is what it looks like to me. So, if she subtracts the 151 whole (or 1812/12) miles from the total of 1820/12, she would have 8/12, or 2/3.

 

Long answer short, she got the right answer, she just expressed it differently.

[Juniper]

1820/12 is right. Don't convert to decimal, just simplify the fraction.

 

1820/12 = 151 8/12 = 151 2/3

 

Okay, I see it. I am going to show this to her so she can see the extra steps. I like MM for the most part, but I do miss having a teachers manual. :D