1. 10-4 Common Logarithms Objective:
To identify the characteristic and the mantissa of a logarithm.
To find common logarithms and antilogarithms.

2. Vocabulary Mantissa – The decimal portion of a logarithm.
Characteristic – The integer portion of a logarithm.
Antilogarithm – When you are given the logarithm of a number and asked to find the number, you are finding the antilogarithm.

3. Example 1 If log 1.2 ≈ .0792, find each of the following. log 120

4. Example 2
log 120 ≈
Characteristic = 2
Mantissa = .0792

5. Example 3
log ≈
Characteristic = -4 (use the integer to the left)
Mantissa = (add the opposite of the characteristic)

6. Example 4
Use a scientific calculator to find the antilogarithm of
log x = 3.073

7. Assignment
10-4 pg 620 #12-24 even