Significant Digits By Michelle Lamary and and Caitlin Ostrowski
Counting Significant Digit Rules 1. All non-zero digits are significant (725, 2, 12) 2. Trapped zeros are significant (101, 2003) 3. Ending zeros are significant only if the decimal point can be seen (100., 1.10, 100, 20) 4. Leading (beginning) zeros are never significant (0.001, 0.9)
Example
Example 1 - Answer Rule 1 – 4 sig digs non-zero digits Rule 1 – 4 sig digs non-zero digits
Example 1 - Answer Rule 1 – 4 sig digs non-zero digits Rule 1 – 4 sig digs non-zero digits Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros
Example 1 - Answer Rule 1 – 4 sig digs non-zero digits Rule 1 – 4 sig digs non-zero digits Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 2 ending zeros Rule 3 – 2 ending zeros
Example 1 - Answer Rule 1 – 4 sig digs non-zero digits Rule 1 – 4 sig digs non-zero digits Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown
Example 1 - Answer Rule 1 – 4 sig digs non-zero digits Rule 1 – 4 sig digs non-zero digits Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros
Example 1 - Answer Rule 1 – 4 sig digs non-zero digits Rule 1 – 4 sig digs non-zero digits Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros 10 Significant Digits 10 Significant Digits
Example
Example 2 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers
Example 2 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 1 sig dig trapped zero Rule 2 – 1 sig dig trapped zero
Example 2 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 1 sig dig trapped zero Rule 2 – 1 sig dig trapped zero Rule 3 – 1 ending zero Rule 3 – 1 ending zero
Example 2 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 1 sig dig trapped zero Rule 2 – 1 sig dig trapped zero Rule 3 – 1 sig dig ending zero with decimal point is shown Rule 3 – 1 sig dig ending zero with decimal point is shown
Example 2 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 1 sig dig trapped zero Rule 2 – 1 sig dig trapped zero Rule 3 – 1 sig dig ending zero with decimal point is shown Rule 3 – 1 sig dig ending zero with decimal point is shown Rule 4 – beginning zeros are not significant (3 beginning zeros) Rule 4 – beginning zeros are not significant (3 beginning zeros)
Example 2 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 1 sig dig trapped zero Rule 2 – 1 sig dig trapped zero Rule 3 – 1 sig dig ending zero with decimal point is shown Rule 3 – 1 sig dig ending zero with decimal point is shown Rule 4 – beginning zeros are not significant (3 beginning zeros) Rule 4 – beginning zeros are not significant (3 beginning zeros) 4 significant digits 4 significant digits
Example
Example 3 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number
Example 3 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros
Example 3 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 ending zeros Rule 3 – 2 ending zeros
Example 3 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown
Example 3 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros
Example 3 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros 3 significant digits 3 significant digits
Example
Example 4 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers
Example 4 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros
Example 4 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 2 ending zeros Rule 3 – 2 ending zeros
Example 4 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 sig digs (2 ending zeros but decimal point is NOT shown) Rule 3 – 0 sig digs (2 ending zeros but decimal point is NOT shown)
Example 4 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 sig digs (2 ending zeros but decimal point is NOT shown) Rule 3 – 0 sig digs (2 ending zeros but decimal point is NOT shown) Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros
Example 4 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 sig digs (2 ending zeros but decimal point is NOT shown) Rule 3 – 0 sig digs (2 ending zeros but decimal point is NOT shown) Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros 2 significant digits 2 significant digits
Example
Example 5 - Answer Rule 1 – 2 sig digs non-zero digits Rule 1 – 2 sig digs non-zero digits
Example 5 - Answer Rule 1 – 2 sig digs non-zero digits Rule 1 – 2 sig digs non-zero digits Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros
Example 5 - Answer Rule 1 – 2 sig digs non-zero digits Rule 1 – 2 sig digs non-zero digits Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 ending zeros Rule 3 – 2 ending zeros
Example 5 - Answer Rule 1 – 2 sig digs non-zero digits Rule 1 – 2 sig digs non-zero digits Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown
Example 5 - Answer Rule 1 – 2 sig digs non-zero digits Rule 1 – 2 sig digs non-zero digits Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros
Example 5 - Answer Rule 1 – 2 sig digs non-zero digits Rule 1 – 2 sig digs non-zero digits Rule 2 – 0 sig dig trapped zeros Rule 2 – 0 sig dig trapped zeros Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 3 – 2 sig digs ending zeros with decimal point shown Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros 4 significant digits 4 significant digits
Example
Example 6 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number
Example 6 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule sig digs trapped zeros Rule sig digs trapped zeros
Example 6 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule sig digs trapped zeros Rule sig digs trapped zeros Rule 3 – 0 sig digs ending zeros Rule 3 – 0 sig digs ending zeros
Example 6 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule sig digs trapped zeros Rule sig digs trapped zeros Rule 3 – 0 sig digs ending zeros (decimal point is shown) Rule 3 – 0 sig digs ending zeros (decimal point is shown)
Example 6 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule sig digs trapped zeros Rule sig digs trapped zeros Rule 3 – 0 sig digs ending zeros Rule 3 – 0 sig digs ending zeros Rule 4 – beginning zeros are not significant (7 non significant beginning zeros) Rule 4 – beginning zeros are not significant (7 non significant beginning zeros)
Example 6 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule sig digs trapped zeros Rule sig digs trapped zeros Rule 3 – 0 sig digs ending zeros Rule 3 – 0 sig digs ending zeros Rule 4 – beginning zeros are not significant (7 non significant beginning zeros) Rule 4 – beginning zeros are not significant (7 non significant beginning zeros) 1 significant digit 1 significant digit
Example
Example 7 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers
Example 7 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros
Example 7 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 0 sig digs ending zeros Rule 3 – 0 sig digs ending zeros
Example 7 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 0 sig digs ending zeros (decimal point NOT shown) Rule 3 – 0 sig digs ending zeros (decimal point NOT shown)
Example 7 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 0 sig digs ending zeros (decimal point is NOT shown) Rule 3 – 0 sig digs ending zeros (decimal point is NOT shown) Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros
Example 7 - Answer Rule 1 – 2 sig digs non-zero numbers Rule 1 – 2 sig digs non-zero numbers Rule 2 – 4 sig digs trapped zeros Rule 2 – 4 sig digs trapped zeros Rule 3 – 0 sig digs ending zeros Rule 3 – 0 sig digs ending zeros Rule 4 – 0 beginning zeros Rule 4 – 0 beginning zeros 6 significant digits 6 significant digits
Example
Example 8 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number
Example 8 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros
Example 8 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 1 ending zero Rule 3 – 1 ending zero
Example 8 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 sig digs ( 1 ending zero, but decimal point is NOT shown) Rule 3 – 0 sig digs ( 1 ending zero, but decimal point is NOT shown)
Example 8 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 sig digs ( 1 ending zero, but decimal point is NOT shown) Rule 3 – 0 sig digs ( 1 ending zero, but decimal point is NOT shown) Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros
Example 8 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 sig digs ( 1 ending zero, but decimal point is NOT shown) Rule 3 – 0 sig digs ( 1 ending zero, but decimal point is NOT shown) Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros 1 significant digit 1 significant digit
Example
Example 9 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number
Example 9 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros
Example 9 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 6 ending zeros Rule 3 – 6 ending zeros
Example 9 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 6 sig digs ending zeros with decimal point shown Rule 3 – 6 sig digs ending zeros with decimal point shown
Example 9 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 6 sig digs ending zeros with decimal point shown Rule 3 – 6 sig digs ending zeros with decimal point shown Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros
Example 9 - Answer Rule 1 – 1 sig dig non-zero number Rule 1 – 1 sig dig non-zero number Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 6 sig digs ending zeros with decimal point shown Rule 3 – 6 sig digs ending zeros with decimal point shown Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros 7 significant digits 7 significant digits
Example
Example 10 - Answer Rule 1 – 4 sig digs non-zero numbers Rule 1 – 4 sig digs non-zero numbers
Example 10 - Answer Rule 1 – 4 sig digs non-zero numbers Rule 1 – 4 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros
Example 10 - Answer Rule 1 – 4 sig digs non-zero numbers Rule 1 – 4 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 ending zeros Rule 3 – 0 ending zeros
Example 10 - Answer Rule 1 – 4 sig digs non-zero numbers Rule 1 – 4 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 ending zeros (Decimal point is NOT shown) Rule 3 – 0 ending zeros (Decimal point is NOT shown)
Example 10 - Answer Rule 1 – 4 sig digs non-zero numbers Rule 1 – 4 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 ending zeros Rule 3 – 0 ending zeros Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros
Example 10 - Answer Rule 1 – 4 sig digs non-zero numbers Rule 1 – 4 sig digs non-zero numbers Rule 2 – 0 sig digs trapped zeros Rule 2 – 0 sig digs trapped zeros Rule 3 – 0 ending zeros Rule 3 – 0 ending zeros Rule 4 – 0 leading zeros Rule 4 – 0 leading zeros 4 significant digits 4 significant digits
Extra Practice
Extra Practice Answers