## Thursday, November 09, 2006

### Oh No I goofed Again

Here is a problem that I completed am I correct? Leave a comment on what I did correct and where a mistake could be. Please explain to me how to do this question correctly.

apuya_soldier_841 said...

it is wrong because the real answer i think is 6 7/13.

first of all, you got the mixed number right [6] and the numerator right [7]. the wrong thing is the denominator. [12]. what you might have done wrong is add 1 to 49 - 36, while you should have just left it. you might have thought that you had to add 1 to the equation to give the one-number-space, while when you subtract the one-number-space is there already.

i got it by 49 [the next perfect square] - 36 [the previous perfect square] = 13. so then the denominator is 13. then 36's square root is 6, so 6 is the mixed number. then 49 - 42 = 7. so then we get 6 7/13.

tears_77 said...

He said the square root of 42 is
6 7/12.

What Mr. H did correct:

His whole number was right. He probably looked at the chart or did the shortcut.

Shortcut:
Find the factor of the perfect square before the number you are trying to solve.

In this case the perfect square before 42 is 36. So when you looked at your chart the factor of 36 is 6x6 so the whole number is 6.

What Mr. H did wrong:

When he was counting the numbers when he was trying to find the numerator he included the first perfect square.

This is what he did:
(36 37 38 39 40 41 42) 43 44 45 46 47 48 49

One more way he could get it wrong:

By subtracting the number you are trying to solve from the perfect square AFTER the number.

In this case, he could have subtract 49- 42 = 7. Because 49 is the perfect square after 42.

To help you avoid that mistake I'll tell you another shortcut that will make things faster and easier.

Shortcut:
You subtract the perfect square before the number you are trying to solve from the number you are trying to solve.

In this case the perfect square before 42 is 36. So 42-36 = 6 so 6 is the numerator.

What else he did wrong:

He said the denominator is 12 which is wrong. Probably when he was doing the shortcut, he subtracted 1 from the difference.

Shortcut:
You subtract the first perfect square from the next perfect square.

In this case 36 is the perfect square BEFORE 42 and 49 is the perfect square AFTER 42. So 49-36=13. So 13 is the denominator.

So he shouldn't have added one more step to the shortcut.

Mr. H said...

Great job thanks for commenting you two. Anyone else up for the challenge?

Harbekc

michelle 8-16 said...

Mr.H, you got this question wrong. The right answer would be 6 6/13.
This is how toget the answer:

1)Figure out the 2 perfect squares the number is in between. In this case, the 2 perfect squares are 36 and 49.

2)Then figure out the factors of the 2 perfect squares.
36 is 6
49 is 7

The whole number then would be 6.

3)Next you have to find out the denominator. To get the denominator, subtract the lower perfect square from the larger perfect square.
49-36=13

4)To get the numerator, subtract the first perfect square from square root your trying to figure out.
42-36=6

Therefore the answer is 6 6/13

Mr.H you miscounted the numbers between 36 and 49 to get the denominator. You didn't include 49. You subtracted the wrong numbers to get the numerator. You subtracted 42 from 49 instead of 36 from 42.

Anonymous said...

i dont understand anything