Practice - Scientific Notation, Rounding, and Significant Figures

6. Do each calculation and express to the appropriate number of significant figures.
   1. 1.23056 + 67.809 = 69.040
   2. 23.67 - 500 = - 500
   3. 890.05 x 12.3 = 1.09 x 10⁴
   4. 324.55 - 6104.5/22.3 = 51
   5. 285.3 x 10⁶ - 12.000 x 10³ x 22.8954 = 2.850 x 10⁸
   6. 0.0045 x 30,000.0 + 283 x 12
      = (0.0045 x 30,000.0 = 135 ; If the calculation stopped here, you'd round this to two sig figs and say it was 140. But, the calculation goes on to add this number to the product of the next two numbers, so we just need to remember that it would be rounded to the 10s place after the addition step.)
      + (283 x 12 = 3,396 ; This would be rounded to two sig figs 3,400 if calc stopped here. So now, after the addition, we need to round off the answer to the 100s place. The 100s place is less precise than the 10s place, so this part of the sum limits the precision of the answer. This follows the rule for addition.)
      = 3.5 x 10³ or 3,500
   7. 869 x (1255 - 3.45 x 10³)
      = 869 x (- 2.20 x 10³)
      = - 1.91 x 10⁶
      (needed to consider how many sig figs would remain after the subtraction step)