### 20120229: What's Wrong with this Solution?

Refer to the set of solution written in the board.
Identify as many error that you can spot and pen them in the comments.

After discussion:

1. errors
1) Did not convert all fractions to the same denominator
2) did not same the mixed number into an improper fraction in working
3) the answer is wrong as it should be a negative number not a positive number.

1. For error 1, it is not all fractions but some fractions.

2. Line 1 : the error is all the fraction was not converted into improper fractions.

Line 2 : the (1 9/27) is not converted to improper fraction .

Line 3 : The ( 1 1/3) was not converted into improper fraction, hence , we cannot subtract the 5.

1. 1) the addition and subtraction fraction was not converted into improper fraction.
2) if it was not converted into improper fraction, it will be harder to calculate and sometimes we will calculate wrongly.

3. Line 2: The 1 is written wrongly and it should be a 2.
Line 3: The number, 5 is supposed to be 10 as the line before (Line 2) has a wrong number, thus affecting the answer.
Line 4: The answer is wrong as the number, starting from Line 2 is wrong, therefore it has changed the answer.

4. !) opened the bracket without improper fraction.
2) the 1 4/5 is not in improper fraction.
3) the answer does not have a negative sign.
4) the sequence is not "+ then -" but "- then +".

1. number 1, 2 and 4 is in line 1
number 3 is in line 4

2. why?????????

3. why are you trying to say

4. 1) open bracket without improper fraction so the answer is different from the original answer.
2) it should be improper fraction so that the answer is correct.
4) when i was in p4 the math teacher told me that i should do the divide then multiply then minus then plus

5. Line 4 : The answer should have a - sign
Line 1: The first fraction is not the answer to the equation of 1 1/3 3
Line 1: Should change all mixed numbers to improper fractions

1. Cassandra said : What u talking about?

2. what do you mean when you say what are you talking about

6. This comment has been removed by the author.

7. line 1: 1 1/27 should be 2 10/27 and need to convert 1 4/5 to 9/5 before multiplying
line 3-4:1 1/3 - 5 =3 2/3 answer should be negetive

1. (1 1/3)^3 = 4/3^3
=64/7
=2 10/27

8. Line 2: 1 and 1/1 was converted into one, when it was in fact 2. 1*5 should be 2*5
Line 3: The error from Line 2 was carried over. 2*5 is 10.
Line 4: The error was carried over, and the answer was calculated wrongly, as the number should be lower, and the fraction part should still be 1/3. 1 and 1/3-10= -9 and 1/3.

1. There is more: Line 1: The first number to the power of three should be converted to improper fractions first, therefore the number should be 64/27, or 2 and 10/27.
Line 2: The error was carried over, 1 and 9/27 should be 2 and 18/27.
Line 3: The error was carried over, 1 and 1/3 should be 2 and 2/3

2. Line 1: Error because trying to multiply the number to the power of three will give you the wrong answer if it is a mixed number.

9. Line 1: 1 1/3 to the power of 3 is not 1 1/27
Line 2: 1 4/5 should be converted into improper fraction
Line 3: because of the Line 2 error, it should not be 5 but should be 11 4/5 instead

10. In line 1, 1 1/3 is not equal to 1 1/27

In line 2, multiplication should be worked out first

In line 4, 1 1/3-5 is -3 2/3 not +3 2/3

All mixed numbers should be converted to improper fractions

1. Where is the power of 1 1/3? 0_o?

11. line 1:1 and 1/3 times the power of 3 is not 1 and 1/27. the mixed number should be changed into the improper fraction before doing the cancellation

line 4 : the mixed fraction is smaller than 5 thus the answer should be negative.

1. Good explanation! Thanks! >-<

12. 1. line one (1/1/3)3 is wrong 'cause it doesn't give u 1/1/27.
2. there is another mistake in line 1 where -1/4/5 %(divide) 4/25 DOES NOT equal to 1/1/1 x5/1.
3. since line one has those mistakes, the calculations after that is also wrong.Such as -1x5 and 1/9/27.
4.that means the answer 3/2/3 is wrong.

1. why is there a percentage ?

13. 1) Line 1. The mixed fraction 1 4/5 should be changed to improper fraction as after you use the cross cancellation method the answer would not tally and it would affect the final answer.

2) Line 3. The answer is supposed to be a negative answer as it is a smaller number subtraction(-) a bigger number and it is not addition(+) and the numbers cannot change its position.

3) Line 1. The mixed fraction for 1 1/3 3 is not 1 1/27

1. Edit 3

Line 1. The mixed fraction for 1 1/3 power 3 is not 1 1/27

2. Opps! No such thing called cross cancellation! Sorry! :(

14. 1)they did not convert to improper fraction before they cube root the Fraction 1 1/3 3
2)they did not convert to improper fraction before multiplying 1 4/5
3)the final answer is wrong as there is no negative sign (1 1/3 minus 5 = to -3 2/3 not 3 2/3)

15. line 1 - 1 1/3 does not equal to 1 1/27
line 2 they should multiply then do addition/ subtraction
line 4- 1 1/3 - 5 is not 3 2/3

1. line 1- is 1 1/3 to the power of 3 not 1 1/3