Rounding with calculator

[sfad]

So when we are doing calculations, we need to simplify at each step to 2 decimal places? So in no. 1. below, I have used the 2 decimal places, while for no. 2. I used the exact figures. The answers are clearly going to be different and in the AM section we get different results. So which is correct?
1.
(0.33x0.741)+(0.67x0.3370)=47.03%
2.
[(1/3)x(0.741)] + [(2/3)x(0.3370)=47.17%

 

[tomscott88]

I wouldnt do any rounding at any calculation stage. Only round up/down when you get to the final answer. So in the example that you gave the 47.17% would be the correct representation of the answer.

 

[cpk123]

please keep Decimal 9 - max possible for your calculator settings
do the rounding at the final instance - only when you commit your answer to the paper.

 

[ltj]

Not always.
2012 AM paper, Question 8 - Derivatives
Asks you to reduce equity allocation/beta, increase fixed income/reduce duration.
If you don’t round until your final answer, you’ll be one contract off on each answer. Small contradiction to the above, but you would want to round your futures contracts to the whole number at each stage (changing allocation %, increase/decrease beta/modified duration) before doing the final addition/subtraction to arrive at your answer.

 

[sfad]

cpk123 wrote:
please keep Decimal 9 - max possible for your calculator settings
do the rounding at the final instance - only when you commit your answer to the paper.

I agree and I will normally round at the final answer.
BUT cfai 2006 paper, question 7C, they round at each instance and use 0.33 and 0.67. Hence we get different answers.