1. ROUNDING OFF COUNT THE NUMBER OF DIGITS NEEDED FROM THE LEFT AND LOOK AT THE NEXT NUMBER: A IF THE DIGIT IS 0, 1, 2, 3, 4 DISREGUARD THESE VALUES B IF THE DIGIT IS 6, 7, 8, 9 ROUND THE PREVIOUS DIGIT, ROUND UP C IF THE DIGIT IS 5 FOLLOWED BY ANY VALUES AFTER IT, ROUND UP D IF THE DIGIT IS 5 ALONE OR FOLLOWED BY ZEROS ROUND TO THE EVEN VALUE FOR THE PREVIOUS DIGIT

2. EXAMPLES A. 56.7112 TO THREE DIGITS 56.7112 WOULD BECOME 56.7 B. 197.336 TO FIVE DIGITS 197.337 WOULD BECOME 197.34 C. 225.513 TO THREE DIGITS 225.513 WOULD BECOME 226 D. 486.45 TO FOUR DIGITS 486.45 WOULD BECOME 486.4 E. BUT 486.35 TO FOUR DIGITS 486.35 WOULD BECOME 486.4 ALSO.

3. SIG FIG RULES A. ALL NONZERO DIGITS ARE SIGNIFICANT B. CENTER “0” ARE ALWAYS SIGNIFICANT C. LEADING “0” ARE NOT SIGNIFICANT D. TRAILING “0” ARE ONLY SIGNIFICANT IF THERE IS A DECIMAL IN THE NUMBER.

4. Examples SIG FIG 56.7112 SIX SIG FIG 107.036 SIX SIG FIG 0.0255 THREE SIG FIG 48.600 FIVE SIG FIG 450000 TWO SIG FIG

5. SCINOT RULES USE ONLY THE SIG FIG OF THE ORIGINAL VALUE MOVE THE DECIMAL TO BEHIND THE FIRST SIG FIG ON THE LEFT (one digit LEFT of decimal) COUNT THE “PLACES” MOVED TO THE NEW DECIMAL POINT FORMAT WITH x 10 + IF ORIGINAL VALUE WAS GREATER THAN ONE - IF ORIGINAL VALUE WAS LESS THAN ONE

6. EXAMPLES OF SCINOT 46600 = 4.66x 10 4.002730 = 2.730 x 10 -3 600.00 = 6.0000 x 10 2.000005 = 5 x 10 -6

7. Percent Values What is the % if 66 g of Iron are in a mixture with a mass of 342g? (66 / 342) X 100 = 19.3%

8. Density Symbols D = density, m = mass, V = volume e = end, s = start D = m / V D of regular objects D = m / (l)(w)(h) D of irregular objects D = m / ( V e – V s ) D of liquids / grains D = (m e – m s) / V

9. Metric System Developed in the 1770’s by a group of scientists from different countries. Based on the number 10,it unifies distance, volume and mass. This system uses prefixes to denote multiples and divisions of the base values.

10. Metric Prefixes Ttera10 12 Ggiga10 9 ddeci 10 -1 Mmega10 6 ccenti 10 -2 Kkilo10 3 mmilli 10 -3 hhecto10 2 μmicro 10 - 6 dkdeka10 1 n nano 10 -9 BASEppico 10 -12

11. Metric coversions T G M K h dk base d c m μ