# What is the default precision of  when not specifying a digit after it?

Posted 8 months ago
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 If the symbol  has no digits after it, what is the precision of the number understood to be?Here is a the sample code: DKReplace = {70.6, 74.2, 80.1, 75.3, 55.6, 55.5, 62.6, 64.9, 80.1, 102.5}; Thank you,Benoit
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Posted 8 months ago
 Numbers entered with a backtick  but without a specified precision are treated as machine precision numbers, which is to say, they are treated just like an undecorated number with a decimal point. A backtick without a number specifying precision is useful when applied to an integer without a decimal point. With a number having a decimal point, the backtick does nothing. You can determine the precision of a number using the Precision function: In[1]:= Precision[70.6] Out[1]= MachinePrecision In[2]:= Precision[70.6] Out[2]= MachinePrecision The symbol MachinePrecision is treated as a constant and is set to the value of $MachinePrecision, which begs the question, "What is $MachinePrecision?" From the documentation: The typical arrangement is that all machine‐precision numbers in the Wolfram Language are represented as "double‐precision floating‐point numbers" in the underlying computer system. On most current computers, such numbers contain a total of 64 binary bits, typically yielding 16 decimal digits of mantissa.