Use a point (period) as the decimal marker, and use spaces to ...

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Use a point (period) as the decimal marker, and use spaces to separate long numbers into easily readable groups ________________.
 
  a. of similar numbers
  b. on a single page
  c. of three
  d. of five

Question 2

For very large round numbers (1 million or greater), use a combination of _________________.
 
  a. numbers and fractions
  b. letters and figures
  c. figures and numbers
  d. numbers and decimals

[daiying98]

Answer to Question 1

c

Answer to Question 2

b

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TYSM

[okolip]

Excellent