20060301
4  Number of Digits and Precision
k
 Number of Digits 
Standard Mode 
The following applies when the check box next to the “Decimal Calculation” item on the Basic 
Format dialog box is not selected.
• Up to 611 digits are stored in memory for integer values. 
• Decimal values up to 15 digits are converted to fraction format and saved in memory. When 
a mathematical expression cannot be converted to fraction format, the result is displayed in 
decimal format.
• Values stored in memory are displayed as-is, regardless of how [Number Format] settings  
(Normal 1, Normal 2, Fix 0 – 9, Sci 0 – 9) are configured (except when a decimal value is 
displayed). 
Decimal Mode
 
The following applies when the check box next to the “Decimal Calculation” item on the Basic 
Format dialog box is selected. 
• Values stored in Ans memory and values assigned to variables have the same number of 
digits as defined for Standard mode values. 
• Values are displayed in accordance with how [Number Format] settings (Normal 1, Normal 2, 
Fix 0 – 9, Sci 0 – 9) are configured.
• Displayed values are rounded to the appropriate number of decimal places. 
• Some applications store values using a mantissa up to 15 digits long and a 3-digit 
exponent. 
k
 Precision 
• Internal calculations are performed using 15 digits. 
• The error for a single mathematical expression (Decimal mode calculation error) is 
±
1 at the 
10th digit. In the case of exponential display, calculation error is 
±
1 at the least significant 
digit. Note that performing consecutive calculations causes error to be cumulative. Error 
is also cumulative for internal consecutive calculations performed for: ^(
x
y
), 
x
      , 
x
!, 
n
P
r
, 
n
C
r
, etc. 
• Error is cumulative and tends to be larger in the vicinity of a function’s singular point(s) and 
inflection point(s), and the vicinity of zero. With sinh(
x
) and tanh(
x
), for example, the 
inflection point occurs when 
x
 = 0. In this vicinity, error is cumulative and precision is poor. 
α
-4-1
Number of Digits and Precision