what exactly is the difference between accuracy and precision?? can we find out accurate and precise value by observing the true and measured value only....??

Accuracy defines how close is the measured value to the actual value whereas the precision of a measurement system, also called reproducibility or repeatability, is the degree to which repeated measurements under unchanged conditions show the same results. 

 

You can find the accuracy and the precise value by observing the true and measured value only given that you have multiple measured values to make any comment on the accuracy as well as the precision of the same.