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Waugh Sheet #2 (Modified Fall 2012)

Addition and Subtraction with Significant Figures

Rules:

1.      1.  All numbers must be in the same power of 10.

2.      2. Line up the decimal points.

3.      3. Now, only refer to the numbers with the same Power of 10.

4. Solve the problem.

5. The solution should have the same number of DIGITS AFTER THE DECIMAL POINT as the number in the operation that has the LEAST number of DIGITS AFTER THE DECIMAL POINT.

4.       6. Then put the solution in Scientific Notation.  Perform on paper without calculator. You are smarter than the calculator!

 Example #1:  2.80 cm  + 17.109 cm = ___?___                                                           2.80   cm   (2 DIGITS AFTER THE DECIMAL PT)                                                       17.109 cm   (3 DIGITS AFTER THE DECIMAL PT)                                                       19.909 cm   (You must report only 2 DIGITS AFTER THE                                                                                    DECIMAL POINT)                                                 Reported Answer = 1.991 x 101 cm

 Example #2:  7.189 x 105 g – 8.9 x 104 g = ___?___ (Make sure to change both numbers to 105 or 104, before you attempt to solve this problem.)                                                                                                7.189 x 105 g                                                  –  0.89   x 105 g                                                      6.299 x 105 g                                                   Reported Answer = 6.30 x 105 g

Directions:  Perform the following operations and report your answers in SCIENTIFIC NOTATIONPROVE ALL work NEATLY ON A SEPARATE SHEET OF PAPER that is STAPLED TO THIS SHEET or your points are VOID.

 Problem Answer #1 1, 025 m  -  28.9 m  = 9.96 x 102  m #2 505 kg + 450.25 kg = 9.55 x 102 kg #3 0.15 cm + 1.15 cm + 2.051 cm = 3.35 x 100 cm #4 9.28 x 103 fg + 8.72 x 102 fg = 1.015 x 104 fg #5 0.55 cm + 36.15 cm + 17.3 cm = 5.4 x 101 cm #6 27.55 x 10-9 g – 15.545 x 10-7 g = - 1.5270 X 10__6 g #7 7.397 x 108 ng + 8.1094 x 109 ng = 8.8491 x 109 ng #8 9.999 x 103 pL – 8.985 x 102 pL= 9.101 x 103 pL #9 9.61 x 105 mL + 5 x 104 mL = 1.01 x 106 mL #10 22.10 mL – 10.5 mL = 1.16 x 101 mL