The United States has a labor force of approximately people. The table shows the distribution of the labor force among five categories of occupations. Distribution represents a percentage of the total population. Categories Distribution of U. S. Labor Force
Farming, forestry, and fishing 0.01
Manufacturing, extraction, transportation, and crafts 0.20
Managerial, professional, and technical 0.37
Sales and office 0.24
Other services 0.18
a. Approximately how many people work in the "Sales and office" category? Show the answer in scientific notation.

b. Find the difference between the number of people working in the "Farming, forestry, and fishing" category and the number of people working in the "Managerial, professional, and technical" category. Show the answer in scientific notation.