significant digits unit 1 – pp 56 – 59 of your book mrs. callender
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Significant DigitsUnit 1 – pp 56 – 59 of your book
Mrs. Callender
Significant Digit Rules
1. All nonzero numbers are significant.
1.345 g has 4 significant digits.
2. Zeros between nonzero numbers are significant.
1.05 g has 3 significant digits.
Significant Digit Rules
3. Zeros before nonzero numbers but after the decimal place are NOT significant.
0.0033 g has 2 significant digits.0.0033 g the zeros are PLACEHOLDERS
4. Zeros after the decimal AND after nonzero numbers are significant.
1.500 g has 4 significant digits.1.500 g the zeros are significant.
Significant Digit Rules
5. Zeros both at the end of a number but to the
left of a decimal points is NOT significant. 1,000 L has 1 significant digit1,000 L the zeros are PLACEHOLDERS
What about 200 red cars?
Is there a measuring device for cars?
Counting numbers have an infinite number (∞) of significant digits.
Conversion factors are exact: 1 inch = 2.54 cm
This has ∞ number of significant digits
Rounding rules for number 5.
Math: when rounding with a 5 the number would get “rounded up”.
4.5 rounds to 5
In Science……Odd numbers: 1,3,5,7,9 Round up with 5
Even numbers: 0,2,4,6,8 No rounding with 5
Round 1.35 cm to 2 significant digits.
Round 1.45 cm to 2 significant digits.
1.4 cm
1.4 cm
Ad
ditio
n a
nd
S
ub
tractio
nAdd/Subtract then round to the data
with the fewest number of DECIMAL places.
24.5001 cm
123.45 cm
+ 0.378 cm
148.3281 cm
3 decimal places
2 decimal places
4 decimal places
Answer can only have 2 decimal places.
Round 148.3281cm to 148.33 cm
**
Mu
ltiplic
atio
n a
nd
D
ivis
ion
Multiply/Divide then round to the data with the fewest number of Significant Digits.
24.5001 cm
X 0.378 cm
9.2610378 cm2
3 sig. digs
6 sig. digs.
Answer can only have 3 significant digits.
Round 9.2610378 cm2 to 9.26 cm2
**
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