G8

Copyright © Swun MathCopyright © Swun Math Grade 8 Unit 3 Lesson 3 C TE

Input/Model

(Teacher Presents)

Directions: Simplify. Write the sum or the difference in scientific notation.

1. (2.75 × 103 ) + (9.1 × 103 )

Solution:

• Since the powers of ten are the same, use the
  distributive property to combine the lead numbers
  and add them.


• 2.75 × 10^3 + 9.1 × 10^3


• (2.75 + 9.1) × 10^3 Add first (parentheses)


• 11.85 × 10^3  Not in Scientific Notation


• 11.85 needs to change to 1.185 for Scientific
  Notation


• Answer: 1.185 × 10^4
  or


• Convert to standard form:


• 2750 + 9100 = 11,850


• Convert solution 11,850 into Scientific Notation
  form.
  Answer: 1.185 × 104
  2. (6.6 × 10 –^5 )– (3.5 × 10 –^5 )

Solution:

• Since the powers of ten are the same, use the
  distributive property to combine the lead numbers
  and add them.


• 6.6 × 10-5 – 3.5 × 10-5


• (6.6 – 3.5) × 10-5 Subtract first (parentheses).


• 3.1 × 10-5


• Answer: 3.1 × 10-5
  or


• Convert to standard form:


• 0.000066 – 0.000035= 0.000031


• Convert solution 0.000031 into Scientific Notation
  form.
  Answer: 3.1 × 10 –5