## Tuesday, 17 January 2017

### Finding Cube Root... What's wrong with this working?

Question: Find the cube root of 13824

Read the working carefully.
• Highlight area(s) that you think is incomplete
• Identify an 'critical' mistake - because of the way the working is presented

#### 31 comments:

1. 24x 24x 24 is not = to 24

1. He should write it as cube root of 13824 = 24

2. 24 x 24 x 24 is not equal to 24

1. He did not include the cube root sign

3. 24*24*24 is not equal to 24, he should put Cube root of 13824=24

1. He should finish the prime factorisation with 1

4. In lines 3 and 4, 24*24*24 is not equal to 24.

5. he didn't complete the factorisation
24x28x24 dosent equal to 24

6. not systematic. cannot red what is written the end product of the prime factorisation is not 1 but 3 and 13824 is not 24

1. it is read not red

7. Line 1: 3824 divided by 2 is not 6912

8. he did not put the square root in the 13824

9. He did not use the cube root so by reading his working it only tells me that 24 x 24 x 24=24 which is wrong

10. 24x24x24 is not equal to 24.

11. 13824 is not equals to 24

1. He did not end of the factorization completely

12. he forgot to put the square root before his answer

1. Oops I mean cube root

13. In line 4, it should be cube root 13824=24 as 13824 is not equal to 24

14. On line 4, He said that 13824 equals to 24.

15. 24x24x24 is not equal to 24 as 24 is the square root of 13824

16. 24x24x24 is not equal to 24.

17. he did not complete the prime factorisation and 24 x 24 x24 is not equal to 24

18. It says that 24x24x24
= 24
Which is incorrect

19. 24 x24 x24 is not 24

20. Critical mistake:
Line 4 is incorrect as 24*24*24 is not equal to 24. The person must put the cube root in front.

21. In line 3, 24 x 24 x 24 and then in line 4, he put it to be equal as 24 which is wrong

22. 13824 is not equal to 24 and 24 to the power of 3 is not equal to 24.

23. 24x24x24does not produce the number 24

24. For his working, he wrote: 24 x 24 x 24=24, which is wrong.

25. In Lines 3 & 4, his working states 24x24x24=24, which is wrong

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